Doom
Age of Conan
Duke Nukem 3D
Hunter Hunted
Heroes of Might and Magic 3

1. Republic: The Revolution
2. Deus Ex (it's all good, but it would be here just for the Wan Chai marketplace)
3. Heroes of Might and Magic 2 Gold (I prefer the new town music)
4. Tropico
5. Sim City 4 (writing stuff like this would be my dream job)
6. Railroad Tycoon 3 >.>

did anyone mention anything by Stephane Picq? It's kinda a neat coincidence I noticed this thread just as I was discussing the Megarace 1 soundtrack on the irc. Also Dune (the game music, not the audio CD malarkey they released at some point). So there's two for ya.

Hard to top these greats ^_^
1: Ecco The Dolphin
2: Chrono Cross
3: Diablo 1,2
4: Final Fantasy
5: The Witcher
B-Sides
1: America McGee's Alice
2: Jade Empire
3: Serious Sam
4: Trickstyle
5: Unreal Original
--UT, 2k4, 2k5, Ut3

1. Space Station Silicon Valley - I love this game, and I love this soundtrack. "The Battery Farm" and "The Engine Room" are my favorites.
2. Jet Grind (Set) Radio - "That's Enough" is simple but great. Not to mention nearly every other song in-game really works.
3. Diddy Kong Racing - Every song has a really fast pace and is switching gears every fifteen seconds, but it's fun to listen to.
4. Unreal Tournament (99) - Some of 'em. This is pretty much the first legit computer game I played, and also the first time I heard this sort of music. Awesome.
5. Banjo-Kazooie. Not much to say - I love it.

I like the way the characters speak. That's really funny.

Fuck yes, ECCO.
I honestly think Ecco the Dolphin is the best console game ever. Amazing music.

Most Bungie games have excellent soundtracks, including:
Myth: The Fallen Lords
Myth 2: Soulblighter
Marathon
Halo
Grim Fandango, Crusader: No Remorse, and Baldur's Gate 2 also have excellent soundtracks.

Come on guys! No Monkey Island = Fail
1. Secret of/Curse of Monkey Island
2. HOMM 2
3. Super Mario Galaxy
4. DOOM
5. Super Castlevania 4

I'll just throw in 2, but those 2 deserve it.
1. Turrican - http://www.youtube.com/watch?v=kwaTdxHU4l8
2. Chrono Trigger - http://www.youtube.com/watch?v=VDANk9wjw3k
Damn, now I want to play Chrono Trigger again!

Contra Hard Corps
Outcast
Grim Fandango
Ecco the Dolphin
Quake II

Total Annihilation
Quake 2
Unreal
Rome: Total War
Command & Conquer

Tropico!!!

1: Homeworld
2: Jet Set Radio
3: Command & Conquer: Red Alert 2
4: Quake 2
5: Unreal
I'm very deeply disappointed that no one even mentioned Homeworld... Especially considering that the soundtrack won awards on its own.

I'm a real fan of the 16-bit era and it's music!
So I'll go;
1) - Sonic 3 (Angel Island Zone, Ice Cap Zone
2) - Super Mario World
3) - Sonic 2 (Metropolis Zone! Too good!)
4) - Aladdin (The Megadrive one, I defy you to not enjoy the Turban Rock track on the desert level!)
5) - Comix Zone (A lot of the tracks here sound grungy and reminiscent of Pearl Jam and that whole era of music. Quite different for a 16-bit game I thought!)
Honourable mention for Zelda: LttP and World Cup Italia '90. There are others, but we'd be here all day! :)