These are my favourite sountracks: (no links, sorry!)

- diablo 2; eerie atmosphere, definitely my favourite..
- baldur's gate 1 & 2; epic!
- anno 1404; very calm and happy music
- witcher 1; beautiful folk music
- doom; bring on the heavy metal! :-)
- eufloria; calming..
- machinarium; sweet!
- syberia; very nice soundtrack
- morrowind/ skyrim; very good sountracks!
- divine divinity; moody..
- arcanum; a nice, full of strings soundtrack!

Edit: how could I forget the last two? :-P

I'm a fan of some of the 16-bit music from my SNES days...

Flashback - and [url=http://www.youtube.com/watch?v=vAek8B76y6g]ending credits.

Also Super Metroid (Full Soundtrack)

The Sims 2

Europa 1400

Crusader No Remorse: 'The Traveler'
http://www.youtube.com/watch?v=wwG5BJtZBCU&list=PLBDAB91E4CC58FFC5

Hexen II: 'The Enchanted Cathedral'
http://www.youtube.com/watch?v=NSN_UuTntRo&list=PLF169DB46035DE0A4

Outlaws: 'Sanchez the Outlaw'
http://www.youtube.com/watch?v=dFWOl9XoxC4

No One Lives Forever: 'El Dorado'
http://www.youtube.com/watch?v=E3PtMTIHMVw&feature=relmfu

Anno 1404: 'Crowned King'
http://www.youtube.com/watch?v=l8AovClBD1I&list=SPC78EAD6B32ADB608

EDIT: and a very hilarious one from Crusader No Regret:
http://www.youtube.com/watch?v=uejvBkXtGmM&list=PLBDAB91E4CC58FFC5&index=15

Beyond Good and Evil OST - Hylian Suite
http://www.youtube.com/watch?v=_p5dLckSz6U

Portal 2 OST - Turret Wife Serenade :)
http://www.youtube.com/watch?v=4anpiZjfR-s

Half Life OST - Ending Theme
http://www.youtube.com/watch?v=oy1lsys2leg

Half Life 2 OST - Lambda Core
http://www.youtube.com/watch?v=1v4882jPvyA

Fez OST - Adventure
http://www.youtube.com/watch?v=76GnOwHorn0

Monaco OST - Prison Life
http://www.youtube.com/watch?v=bfXenMtnchk

Beatbuddy OST - Beatbuddy Swing
http://www.youtube.com/watch?v=71XzIR7ZbLM

Rochard OST - Grinder's Blues
http://www.youtube.com/watch?v=QMit1cmh_1Y

Hedgewars OST - EarthRise Stage
http://www.youtube.com/watch?v=QkLRkyPhcSc

Battle for Wesnoth OST - Still Another Wanderer
http://www.youtube.com/watch?v=YSs0Y06nU0I

DOOM

https://www.youtube.com/watch?v=JxGzsJKg8zw

DOOOOM

https://www.youtube.com/watch?v=Sg37lkE5cuw

DUUKE

https://www.youtube.com/watch?v=BD3VJGDqphM

Blade...I mean Bloodrayne 2 :P

https://www.youtube.com/watch?v=KWUNkhPys4Y

Command and Conquer Hell March 2 (my favorite ^^)

https://www.youtube.com/watch?v=9WqwFhX6Cqg

Totally necroposting.... BUT!

Dear Lord the Darksiders 2 soundtrack is so good. Vey adventorous and epic at the same time. Some exaples:

A fight with "spoiler alert from the first few minutes of the game" song:
https://www.youtube.com/watch?v=txvZSL3DZ2I
It is unedited, so it does sound rough, in the actuall game, it adapts to the situation, so it sounds miles better.

A certail boss theme:
https://www.youtube.com/watch?v=O4lwpYLlVvM
Vey good. Actually reminds of The Witcher games for some reason (instruments used and vocals?)

The whole soundtrack is amazing. Plus, this game has the he most adventorous intro I had ever heard. In game it was just jaw dropping. Just gets you ready for slaying/puzzling/jumping and fighting stuff.

Great game. finished it a while ago, just now rediscovering the brilliant soundtrack. Get it, it is dirt cheap.

but its a good necropost !

ys first steps towards war

https://www.youtube.com/watch?v=yELuvkU32Lg

gynoug stage 1-1
https://www.youtube.com/watch?v=szh3iDfi9zU

Nightshade!




[url=https://www.youtube.com/watch?v=iU976kGLD_s ]Devil may cry [/url](Newest one.)

Chrono Cross.
I used to stay on the map and let this music run in the background, while doing homework.

Does anyone wanna Jam?

Hm won't search for links, but some of my favs:

Myst II-IV - The original had a nice one too but it lacked production value a bit, so i won't include it here. The others are amazing though, i like to listen to them when i get artsy ;)

Baldurs Gate - Throne of Bhaal, some very epic orchestral songs, really like them a lot

Planescape Torment - A bit odd and sometimes irritating, so it fits the game perfectly. I don't think theres a better bar song than in the Smoldering Corpse Bar, also the Main theme is really great, i like how there are several variations throughout the game.

Mass Effect 2 - Quite dark at times but it really fit to the game mood i think. Also, it just was totally epic at times. Suicide Mission theme for example.

The Witcher 1 had an amazing soundtrack, almost every track of it.

Bioshock Series - Not just the period songs but the original score as well, i really like the string pieces.

Honorable mentions:
DX, DX:HR, Unreal, UT... fits the scifi theme pretty well.
Both Alice games.
Gray Matter, although a bit more variation would have been nice
Stalker
Oblivion/Skyrim
Never played them but what i heard from the Silent Hill soundtrack was nice too. One of the best things about the movie at least ;)

Castlevania: Vampire Killer:
https://www.youtube.com/watch?v=C-azpF5LfuQ

DOOM E1M1:
https://www.youtube.com/watch?v=BSsfjHCFosw

Pokemon Emerald Vcitory Road:
https://www.youtube.com/watch?v=Obee0qtFYmI

Anything thats from shadow of the colossus :)
https://www.youtube.com/watch?v=VzfOGO0qJmA (11th colossi theme)

My Fav was Cybernoid 2 on C64, along with Ghostbusters