The Elder Scrolls III: Morrowind
Final Fantasy IV or VII - Tied
Deus Ex
Vampire the Masquerade: Bloodlines
Castlevania: Symphony of the Night

Homeworld and Great Naval Battles (the first one)

Arcanum
Beyond Good and Evil
Half-Life
Quake II
<Reserved for future use>

These are my favs!
1) Planescape Torment.
2) Lands of Lore
3) Civilization II (I can´t get those drums out of my head)
4) Europa Universalis II
5) Rome Total War

In no particular order:
Morrowind
Another world (aka Out of this world)... fantastic music in the intro sequence, without any soundcard at the time : check here [url=]http://www.youtube.com/watch?v=dNeayv-OTK0&feature=player_embedded#[/url]
Diablo / Diablo II
Loom (best use of music ever in a game)
Braid and/or World of Goo maybe ? although the music gets repetitive after a while

Fallout 2
Fallout 2
Fallout 2
Fallout
Fallout