I recently picked up the only Nightwish album I was missing and am now looking to branch out a bit. That last album, "Century Child," is now my favorite, one reason being that they finally got a male vocalist that doesn't make me cringe. Figures it'd be Tarja's last.
I like old Metallica but I've also looked into Megadeth (too many CDs, overload!), Evanescence (not bad but it'd be nice if she knew more than one song), and Leaves Eyes (why is it their best song is only available on a single?). I took quick looks at Therion, Dream Theatre and some others but I'm not sure where to start. I don't have a ton of money to spend on music so I like to get a lot of bang for my buck; I'm not looking to buy an album for one good song.
In general, I like complex and technical guitar and good lyrics. Obviously, I'm a big fan of the whole metal/opera mix. I can't stand the screaming and gutteral groaning that seems so prevailent in the genre. I strongly prefer good and discernable melodies to chaotic cat-strangling.