Oh my. Well this oughta be interesting. At least it should be good for the soul.

I guess I'll refrain from putting up MMOs.

I like green too!

Not finished!:

Battlestations: Midway
BioShock 2
Commandos: Behind Enemy Lines, Beyond the Call of Duty, Strike Force
Commandos 2: Men of Courage
Commandos 3: Destination Berlin
Conflict: Denied Ops
Defense Grid: The Awakening
Deus Ex: Game of the Year Edition
Deus Ex: Invisible War
Dragon Age: Origins
Eufloria
Everyday Shooter
Fallout 3
Far Cry 2
Indigo Prophecy
King Arthur - The Role-playing Wargame
Mass Effect 2
Oddworld: Abe's Exoddus
Oddworld: Abe's Oddysee
The Dig
Thief: Deadly Shadows
Torchlight
Vampire: The Masquerade - Bloodlines
Zeno Clash

Finished/Multiplayer:

Advent Rising
Armed and Dangerous
Audiosurf
BioShock
Braid
Call of Duty 4: Modern Warfare
Call of Juarez
Cogs
Counter-Strike
Counter-Strike: Source
Dark Messiah Might and Magic
Day of Defeat
Day of Defeat: Source
Deathmatch Classic
Far Cry
Grand Theft Auto: Vice City
Grand Theft Auto IV
Half-Life
Half-Life: Blue Shift
Half-Life: Opposing Force
Half-Life 2
Half-Life 2: Episode One
Half-Life 2: Episode Two
Half-Life 2: Lost Coast
Half-Life 2: Deathmatch
Hitman: Codename 47
Hitman: Silent Assassin
Hitman: Blood Money
Indiana Jones and the Last Crusade
Indiana Jones and the Fate of Atlantis
Infernal
Jade Empire
Just Cause
Kane and Lynch: Dead Men
Left 4 Dead
Left 4 Dead 2
Loom
Lost Planet: Extreme Condition
Lucidity
Max Payne
Max Payne 2: The Fall of Max Payne
Monkey Island Special Edition
Ninja Reflex: Steamworks Edition
Osmos
Painkiller: Gold Edition
Portal
Prince of Persia (2009)
Project: Snowblind
Psychonauts
Ricochet
Rogue Trooper
S.T.A.L.K.E.R.: Shadow of Chernobyl
Sam and Max 201: Ice Station Santa
SiN
SiN Episodes: Emergence
Star Wars: Dark Forces
Star Wars: Dark Forces II
Star Wars: Mysteries of the Sith
Star Wars: Jedi Outcast
Star Wars: Jedi Academy
Star Wars: Knights of The Old Republic
Star Wars: Republic Commando
Star Wars Starfighter
Stubbs the Zombie
Team Fortress Classic
Team Fortress 2
Titan Quest
Titan Quest: Immortal Throne
Tomb Raider: Legend
Tomb Raider: Anniversary
Trine
Unreal Gold
Unreal II: The Awakening
Unreal Tournament
Unreal Tournament 2004
Unreal Tournament 3 Black
Watchmen: The End Is Nigh
Windosill

(as of February 8th 2010)

My steam list is easy.

Plants Versus Zombies[s]
[s]Half Life
[s]Half Life: Blue Shift[s]
[s]Half Life: Opposing Force[s]
Team Fortress Classic

Confession: I've never even played TFC.

The Half Life games and TFC are only on steam because I bought them on a compilation disc which didn't contain the actual games, but rather a code redeemable at Valve to download the games. The only official steam purchase is PvZ.

Pathetic, no?

Almost all of my PC games (exceptions: PvZ and Escape Velocity: Nova, and free stuff like Dwarf Fortress) came on shiny plastic. I even waited to play Sam and Max until TellTale released a DVD season set.

I'd play more PC games if I had a gaming laptop. As it stands, I can run Sins of a Solar Empire if I turn a lot of the graphical effects down, but that's about my limit.

I divided my list into categories because I have a fair number of games that are never really "finished", like Civ etc.
I have a number of other non-Steam titles that fall into some of these categories but didn't list them. I should be pleased, I guess, that my finished game list is bigger than the other lists.

Games I am Actively Playing At Least Intermittently:
Left 4 Dead
Left 4 Dead 2
Peggle Deluxe
Killing Floor
Crysis
Audiosurf

Games I Need to Come Back To At Some Point:
Grand Theft Auto IV (Though maybe not - it is way more crappy than I expected).
Torchlight
Alien Shooter 2: Reloaded
Drakensang
Ghost Master
Mass Effect (Finished, but I intend another playthrough before I play ME2)
X-COM: Terror from the Deep
X-COM: UFO Defense

Games I Want to Play but Have Not Yet Played :
Warhammer® 40,000™: Dawn of War® II
RollerCoaster Tycoon 3: Platinum!
Burnout Paradise: The Ultimate Box
Ben There, Dan That!
Crysis Warhead
Oddworld: Abe's Exoddus
Oddworld: Abe's Oddysee
Monkey Island Special Edition
Red Faction: Guerrilla
Sniper Elite
Time Gentlemen, Please!

Games I've Actually Finished or have no further Interest in Playing:
Half-Life 2: Deathmatch
Max Payne 2: The Fall of Max Payne
BioShock
IL-2 Sturmovik: 1946
Dangerous High School Girls in Trouble!
Fallout 3
Far Cry 2
Freedom Force
Freedom Force vs. the 3rd Reich
Ghostbusters: The Video Game
Half-Life
Half-Life 2
Half-Life 2: Episode One
Half-Life 2: Episode Two
Half-Life 2: Lost Coast
Half-Life: Blue Shift
Half-Life: Opposing Force
Mirror's Edge
Plants vs. Zombies
Portal
Prey
Railroad Tycoon 2: Platinum
Sid Meier's Civilization IV (Though I'll likely fire it up on some rainy Sunday someday)
Sid Meier's Civilization IV: Beyond the Sword
Sid Meier's Civilization IV: Colonization
Sid Meier's Civilization IV: Warlords
Sid Meier's Pirates!
Team Fortress 2
Trine

Games I Never Wanted in The First Place:
CivCity: Rome
Crysis Wars
Railroad Tycoon 3
Shattered Union
Sid Meier's Civilization III: Complete
X-COM: Apocalypse
X-COM: Enforcer
X-COM: Interceptor
Sid Meier's Railroads!
Team Fortress Classic

Wow, long lists for some of you. Never thought the Jedi Outcast games were so popular

My steam list is absurdly pitiful

Here's the grand list
Team Fortress 2
Left 4 Dead 2
Batman Arkham

I had the worst computer for years, incapable of running HL2 or anything remotely up there. Deus Ex-Invisible War was played with like 10 fps. Hence, there's a gap between oldies, and new stuff I play now, which almost is all fps, the genre I totally missed out on before. Only starting to catch on to digital downloads, and so far, I like it far better than hard copies, except for the insane DRM games

Alright, let me take a look at this list...

Man, I'm way more of a sampler than I thought I was before tallying this stuff up. There are a ton of games on there that I loved a lot but left sitting when something new and shiny came out.

Left 4 Dead 2
Left 4 Dead
AaAaAA!!! - A Reckless Disregard for Gravity
Assassin's Creed
Audiosurf
Bejeweled 2 Deluxe
Blueberry Garden
Bookworm Adventures Deluxe
Borderlands
Braid
Burnout Paradise: The Ultimate Box
Commander Keen Complete Pack
Commandos 2: Men of Courage
Commandos 3: Destination Berlin
Commandos: Behind Enemy Lines
Commandos: Beyond the Call of Duty
Commandos: Strike Force
Counter-Strike
Counter-Strike: Source
Dawn of War: Soulstorm
Day of Defeat
Deathmatch Classic
Defcon
Defense Grid: The Awakening
Deus Ex: Invisible War
Doom 2
Doom 3
Doom 3: Resurrection of Evil
Dragon Age: Origins
Enemy Territory: QUAKE Wars
Eufloria
Everyday Shooter
F.E.A.R. 2: Project Origin
Far Cry 2
Far Cry 2: Fortunes Pack
Final Doom
Freedom Force
Geometry Wars
Half-Life
Half-Life 2
Half-Life 2: Deathmatch
Half-Life 2: Episode One
Half-Life 2: Episode Two
Half-Life 2: Lost Coast
Half-Life: Blue Shift
Half-Life: Opposing Force
Half-Life Deathmatch: Source
Helldorado
Heretic: Shadow of the Serpent Riders
Hexen
Hexen 2
Hexen: Deathkings of the Dark Citadel
Hitman: Codename 47
Insaniquarium Deluxe
Jagged Alliance 2 Gold
Jagged Alliance 2 Gold: Unfinished Business
Loom
Lost Planet: Extreme Condition
Machinarium
Manhunt
Master Levels of Doom II
Max Payne 2: The Fall of Max Payne
Monkey Island Special Edition
Monster Trucks Nitro
Painkiller: Gold Edition
Peggle Deluxe
Portal
Prototype
Psychonauts
Quake
Quake II
Quake II: Ground Zero
Quake II: The Reckoning
Quake III: Team Arena
Quake III Arena
Quake Mission Pack 1: Scourge of Armagon
Quake Mission Pack 2: Dissolution of Eternity
RedLynx Trials 2: Second Edition
Return to Castle Wolfenstein
Ricochet
S.T.A.L.K.E.R.: Clear Sky
Sam and Max Episode 1
Sam and Max Episode 2
Sam and Max Episode 3
Sam and Max Episode 5
Sam and Max Episode 6
Sid Meier's Civilization IV: Beyond the Sword
Stubbs the Zombie in Rebel Without a Pulse
Team Fortress 2
Team Fortress Classic
The Dig
The Path
The Ultimate Doom
The Void
Trine
Vampire: The Masquerade - Bloodlines
Wolfenstein 3D
Wolfenstein 3D: Spear of Destiny
X-COM: Apocalypse
X-COM: Enforcer
X-COM: Interceptor
X-COM: Terror from the Deep
X-COM: UFO Defense
Zuma Deluxe

Grand Theft Auto IV (haven't been able to play while my main PC is down)
Defense Grid: The Awakening
Team Fortress 2 (multiplayer, no real end)
Left 4 Dead 2 (multiplayer, no end)
Batman: Arkham Asylum
Braid (bought, not installed yet)
Command and Conquer: Red Alert 3 (bought, not installed yet)
Counter-Strike: Source (I was finished with this before version 1.0 released)
Dark Messiah Might and Magic (sold, but it's still registered to my Steam account)
Dead Space (bought, not installed yet)
Half-Life 2
Half-Life 2: Episode One
Half-Life 2: Episode Two
Half-Life 2: Lost Coast
Left 4 Dead (multiplayer, no end)
Mirror's Edge (bought, not installed yet)
Mount & Blade (technically no end, I played a campaign and conquered the world)
Plants vs. Zombies
Portal
Torchlight (bought, not installed yet)
Trine (bought, not installed yet)
World of Goo
X-COM: Terror from the Deep

Oh, man, this is going to be painful.

Left 4 Dead 2
Zombie Driver
Clutch
ARMA II
Audiosurf
BioShock
Borderlands
Call of Juarez: Bound in Blood
Counter-Strike
Counter-Strike: Condition Zero
Counter-Strike: Condition Zero Deleted Scenes
Counter-Strike: Source
Crysis Warhead
Dark Messiah Might and Magic
Day of Defeat
Day of Defeat: Source
Deathmatch Classic
F.E.A.R. 2: Project Origin
Far Cry 2
Far Cry 2: Fortunes Pack
Grand Theft Auto
Grand Theft Auto 2
Grand Theft Auto 3
Grand Theft Auto: San Andreas
Grand Theft Auto: Vice City
GRID
Half-Life
Half-Life 2
Half-Life 2: Deathmatch
Half-Life 2: Episode One
Half-Life 2: Episode Two
Half-Life 2: Lost Coast
Half-Life: Blue Shift
Half-Life: Opposing Force
Half-Life: Source
Half-Life Deathmatch: Source
Hitman: Blood Money
Killing Floor
King's Bounty: Armored Princess
King's Bounty: The Legend
Left 4 Dead
Lost Planet: Extreme Condition
Lucidity
Max Payne
Max Payne 2: The Fall of Max Payne
Monster Trucks Nitro
Operation Flashpoint: Dragon Rising
Osmos
Overlord
Overlord: Raising Hell
Overlord II
Peggle Deluxe
Plants vs. Zombies
Portal
Prey
Project: Snowblind
Ricochet
S.T.A.L.K.E.R.: Shadow of Chernobyl
Serious Sam HD: The First Encounter
SiN
SiN Episodes: Emergence
Speedball 2: Tournament
Strong Bad Episode 1: Homestar Ruiner
Strong Bad Episode 2: Strong Badia the Free
Strong Bad Episode 3: Baddest of the Bands
Strong Bad Episode 4: Dangeresque 3
Strong Bad Episode 5: 8-Bit Is Enough
Team Fortress 2
Team Fortress Classic
The Void
Titan Quest
Titan Quest: Immortal Throne
Tomb Raider: Underworld
Torchlight
Unreal Tournament 3 Black
World of Goo

Yeah, it's been out for a while. It's down to $10 now.

A word of warning, though: it caused my video drivers (Radeon 4870) to freak out and refuse to display at native resolution, even after returning to the desktop. It's a pretty sweet game, though!

Games I've Finished on Steam:

• LOOM
• The Path
• Heroes of Might and Magic V and expansions

Games I've Finish on Other Platforms:

• Braid
• Doom 3
• Doom II
• Final Doom
• Half-Life 2
• Half-Life 2: Episode One
• World of Goo

Games I Haven't Finished:

• 1701 A.D.
• AI War: Fleet Command
• Audiosurf (unending, yes, but I haven't even touched it)
• Blueberry Garden
• Chains
• Cogs
• Commander Keen: Complete Pack
• Crayon Physics Deluxe
• Dark Messiah of Might and Magic
• Darwinia
• The Dig
• Doom 3: Resurrection of Evil
• Eets
• Everyday Shooter
• Gish
• Gratuitous Space Battles
• Gravitron 2
• Gumboy Crazy Adventures
• Heretic
• Hexen
• Hexen II
• iFluid
• Indiana Jones and the Last Crusade
• Indiana Jones and the Fate of Atlantis
• King's Quest Collection
• Mr. Robot
• Multiwinia (multi-player only, right? I haven't touched this one, either)
• Obulis
• Osmos
• Penumbra series
• Quake and expansions
• Quake II and expansions
• Return to Castle Wolfenstein
• The Secret of Monkey Island
• Space Quest Collection
• Torchlight
• Trials 2
• Vigil
• Wolfenstein 3D
• X-Com: UFO Defense

And there are my reasons for making this a pile-clearing year instead of a year of buying new things.

There aren't many completed games on my list, but then I didn't have anything other than BioShock and The Orange Box until the Steam Holiday Sale. I'm currently playing the games in bold, and highly doubt I'll ever play the games in blue.

Beyond Good and Evil
BioShock - Need to get back to this one. I've played it sporadically over the last few months.
Bone: Out from Boneville
Bone: The Great Cow Race
The Dig
Half-Life 2 - I played a bit of this after I purchased it, and realized that FPS games just aren't for me.
Half-Life 2: Episode One
Half-Life 2: Episode Two
Half-Life 2: Lost Coast
Indiana Jones and the Fate of Atlantis
Indiana Jones and the Last Crusade
Indigo Prophecy
Jade Empire
King's Bounty: The Legend - Just started.
King's Bounty: Armored Princess
King's Quest Collection
Loom
Portal
Sam and Max 101
Sam and Max 102
Sam and Max 103
Sam and Max 104
Sam and Max 105
Sam and Max 106
Sam and Max 201
Sam and Max 202
Sam and Max 203
Sam and Max 204
Sam and Max 205
Sniper Elite
Space Quest Collection
Strong Bad Episode 1
Strong Bad Episode 2
Strong Bad Episode 3
Strong Bad Episode 4
Strong Bad Episode 5
Tales of Monkey Island: Chapter 1
Tales of Monkey Island: Chapter 2
Tales of Monkey Island: Chapter 3
Tales of Monkey Island: Chapter 4
Tales of Monkey Island: Chapter 5
Team Fortress 2 - Like HL2, except even moreso since it's online.
Telltale Texas Hold'em
Torchlight - Almost finished.
Wallace and Gromit Episode 1
Wallace and Gromit Episode 2
Wallace and Gromit Episode 3
Wallace and Gromit Episode 4

Audiosurf Played for about a day and a half
Beyond Good and Evil In the last act, must finish this one day
Bioshock (NA) Hate this game, can't enjoy it.
Bookworm Adventures Volume 2 Playing with the missus
Braid Untouched
Call of Duty 4: Modern Warfare played Single Player, would give away if I could
Cogs Played once, untouched since
Indigo Prophecy Untouched
Left 4 Dead Revist every once in a while
Left 4 Dead 2 - Four Pack (preorder) Played maybe 10 times, need to reengage with GWJ community
Mass Effect Loved it, getting ready for 2nd run
Monkey Island Complete Pack Untouched
Multiwinia + Darwinia Untouched
Osmos Untouched
Plants vs. Zombies Played the living S#!+ out of this game,
Pyschonauts Played once, untouched since
S.T.A.L.K.E.R. Clear Sky (ROW) Untouched
STALKER: Shadow of Chernobyl Untouched
The Longest Journey Untouched
Portal (The Orange Box Retail) Loved it
TF2 (The Orange Box Retail) loving it
Half Life 2 (The Orange Box Retail) Loved it
HL2:Ep1 (The Orange Box Retail) Loved it
HL2:Ep2 (The Orange Box Retail) Loved it
The Secret of Monkey Island: Special Edition Untouched
Torchlight Untouched
Trine Untouched
World of Goo Loved it
X-Com Complete Pack played maybe 10 times first time around, Untouched since bought on Steam

I think L4D(or any game with a campaign) can be said to have been "completed". You wouldn't say you didn't "finish" Doom just because you thought the deathmatch multiplayer meant it was unfinishable, would you?

I'll do my list later, but it's rather short compared to you guys, and I think I only have one completion on it.

Co-op is pretty much the only way I play L4D. I dabbled in survival and found it not to my taste, and my brief excursion into vs. left me with many deaths and no kills...so I never went back. Still love co-op, whether the original levels or one of the many downloadable campaigns (the Silent Hill campaign is an amazingly recreation of the PS1 classic).

Installed
Dragon Age: Origins - languishing because L4D2 Zombies ate my brain.
Left 4 Dead 2 - my obsession du jour. Campaign not complete.
TF2
Torchlight - See DA:O
Atari 80 Classics in One - just because.
Half-Life 2 - Stuck in the mines after Ravenholm. /shudder
Left 4 Dead - not as much action as 2, but still #2 on my To Play List
Peggle Deluxe - nope, not complete.
Wallace And Grommit - multiple eps. Really belong to Mrs. Ducki. *She* finished them all.
Portal - Finished it. Love it. Want to have its babies.

Not Installed
Assassin's Creed - why did I buy this? Can't even stand to get through the tutorial. Ugh.
Audiosurf - love it, never reinstalled after Win7. Sublime.
Evil Genius - for Mrs. Ducki to not have to hunt disks.
Fallout 3 - Got to Megaton, got distracted, now Zombies eat my brains. Will eventually see D.C. Some day.
Ghost Master - again, for Mrs. Ducki
Half Life - Never even really started it. Came with Orange Box, I think.
Half Life 2 Episode 1, 2, 2:LostCoast - not even started
Mass Effect - played about an hour. Got Distracted. Must stop buying anything for more than $20 on Steam that's not Multiplayer.
Port Royale 2 - Mrs. Ducki, again.
STALKER: Shadow of Chernobyl - I think it was $5 and people love it. I played an hour and never came back.
Secret of Monkey Island(remaster/remake) - Just because. Maybe I'll play it some day. Maybe it'll just be for the Duckling.
Tropico 3: Steam Special Ed. - Yep, you guessed it. Mrs. Ducki again. She loves these types of games.

That's it. I've finished Portal. Zombies ate my brain. Nothing else matters.

I just did a copy/paste from my steam control panel. Filtering out the useless text only took about 5 minutes.