Civilizations 4 has a lot of good music to, as does Europa Universalis 2 if you like that kind of thing.
Yeah, EU2 has some nice period-specific tracks, but aren't they all pre-existing (aka "not original for the game")?
Some of my favorites:
GUN soundtrack - lots of really good songs here.
Max Payne 2 - "Theme" and "Choice" - Choice always mentally brings me back to the AWESOME final level...I could listen to this song 30x in a row.
Xenosaga series - some great pumping, chanting, epic tracks. The soundtracks are well worth buying.
Beyond Good & Evil - has a few very nice songs, but I can't think of their names right now.
Rome: Total War - lots of adrenaline pumping battle music.
Vampire the Masquerade: Bloodlines - Phenomenal title track!
Ikaruga - simply because the music is synced so perfectly to the action.
ReZ - same as Ikaruga...plus you can add to it!
Descent: Freespace & Freespace 2: Dan Wentz composed some very nice "fight" music for these!
DooM - e1m1 - Anybody who played DooM 1 in its time would be hard pressed to forget this track.
Shadow of the Colossus - for simply being epic.
The Chronicles of Riddick: Escape from Butcher Bay - more adrenaline tracks here
