I've gotten so lazy I'll let my command shell tell you for me. For sure I will check out the soundtracks listed in this thread. edit: StarCraft OST is free here.

Bubble Bobble
Burnout 3
Castlevania
Chrono Cross Original Soundtrack
Contra - Shattered Soldiers
Diablo
Driv3r
Duke Nukem
Evil Genius
F-Zero
Final Fantasy
Front Mission 4
Gitaroo Man
Halo
Halo 2
Jet Set Radio
Katamari Damacy
list.txt
Mario
Max Payne 2 - The Fall of Max Payne
MegaMan
Metal Gear Solid 2 Sons of Liberty
Metal Gear Solid 3 Snake Eater - First Bite Album
Metroid
Parappa the Rapper
Punchout
Ragnarok
Silent Hill 3 Original Soundtrack
Sonic
Super Mario World
Tetris
The Best of LucasArts Original SoundTrack
Vice city
Xenogears
Zelda
Zone of the Enders

Yay! Another "Best of" list. You know how irresistable I find them

Chrono Cross: Utterly astonishing music. Can music be cinematic? If it could, this would be the primo example.

Ninja Gaiden: As I've said before, the only reason I kept playing after I encountered the goddamn birds was because of the soundtrack.

Katamari Damacy: nananananananananananana....

Tales of Destiny: Rather surprisingly good music, I thought.

Faxanadu: I love the opening song.

And I know this isn't a soundtrack exactly, but the version of the Final Fantasy theme found in FF4 (and FF7, if I remember properly) is so beautiful that it has, on more than one occasion, made me cry.

Yes good call. OCremixes rock. I'm a big fan of "The Sky Was Never A Limit" (FF4), by goat.

Ocarina of Time's tracks, especially the orchestrated versions, are fantastic.

I think the old side-scrolling Mario tracks are great, especially those from Super Mario World. I suspect as pieces of music they're terrible, but the nostalgia factor is off the charts.

Toejam and Earl 2 for the Genesis had some great tracks as well. I even went through the trouble of ripping a few to .mp3 from the roms.

Planescape Torment: seconded
Sim City 2000: for some reason I feel the unstoppable urge to add this to my list. Scary.
The underwater level-music of Mario Bros 1
Final Fantasy 6 had great music. Never played FF7 :$

Anything that involves Eric Brosius (Thief, System Shock etc.)
Anything that involves Tim Larkin (music for Myst series)

And jumping into the wayback machine I'll say Cyberwar with an excellent Soundtrack by
Steve Hillage.

Thief series
Fallout series
I havent played the game but friend lended me Driv3r soundtrack and i must say thats a very impressive compilation. Hearing all that fuss about the game, it could very well be that soundtrack was the best thing about the game.

hey! Interstate 76, guys! Shame on you all.

I LOVED the NOLF2 music! If anyone knows where to find it I will be indebted to you!

Katamari Damacy, and to a lesser extent the sequel.
Outcast. Never played the game, but love the music!

This thread reminded me that Video Games Live will be in Boston on the 17th. Bad timing for the Slap&Tickle.

**posted too soon. Looks like it's sold out. Damn. I mean, Great! Woo!

Wow, how could I forget Mega Man 2.
Dr. Wiley's Stage rocks me.

The couple that leap to my mind are both space games.

Ascendancy
Frontier: First Encounters (cheesy midi, but great for the time)

I've been toying with this for a few minutes and cobbled together a few chunks, and let me tell you.... I can definitely tell why the community hasn't kicked out an unofficial soundtrack yet! Sheesh! Talk about cumbersome! Each sound snippet is about 3 seconds long with another 3 second fadeout. The program presumably layers the next snippet automatically, creating a seamless mosaic of music from a predefined series of transitions. I have the file that specifies the transitions and it seems to be rated by 'intensity.' The intensity of the current snippet determines what transition is used to get to the next snippet of one of three different sets of sound: Exploration (the normal background music), Warning (You done did something you shouldn't have!), and Combat (OMFG NINJAS!!!). I'm looking through Audacity features to see if I can merge audio streams to avoid the abruptness of a cut and past transition, but so far the timing seems to be the big thing. Because of the fade-out it is really hard to determine just when the next track should kick in.

Believe me, I'm going to be playing with this whenever I get a chance to, because I really want to see this happen. I'll definitely offer up whatever I get put together once I have it.

Gosh, really? I'll work double hard now!

So far so good! I tried throwing some of the chuncks of the Siberia levels together sequentially and came up with some pretty good sounding audio! A couple pieces seemed out of place, but I'm working on that. At least the timing seems to fall on whole second increments, making this a lot easier than it looked initially! Now I just need to work out some sequencing that makes these wonderful songs sound good! (And a method for quickly adjusting/rearranging said snippets).

As I said, once I have something worth listening to I'll throw it online for anyone that's interested.

From my personal collection:

Guild Wars
Gran Turismo 2
Gran Turismo 3
Gran Turismo 4
Metal Gear Solid: Sons of Liberty
Metal Gear Solid: Snake Eater
Gitaroo Man
GTA Vice City: Box Set (very good)
GTA San Andreas (not so good)
Guilty Gear X,XX, Isuka
Halo 1, 2
Max Payne 2
Prince of Persia: Sands of Time
Street Fighter Tribute Album (oh so good)
Best of LucasArts
Mario & Zelda Big Band Live CD
Black Mages and Volume 2

I also got some remixes for old NES/SNES games. Most of them are from OCRemix. There's some real awesome stuff there.

Some good ones that I own that have not been mentioned yet:

Ico
Morrowind
Einhander

OCremixes are excellent. They also host Relics of the Chozo which is an incredible compilation of music from Super Metroid.