If you're looking for online/download stuff, I can't help you. If you're asking what's good (CD-wise), then here's a partial list of what I use (these are all pretty much soundtracks):
- Brain Powerd
- Brave Fencer Musashi
- Braveheart
- Chrono Trigger
- Chrono Cross
- Conan the Barbarian, Destroyer
- Cutthroat Island
- Dracula: Nocturne in Moonlight (original name of Castlevania: Symphony of the Night)
- Dracula Battle
- El Hazard
- Elemental Gearbolt
- Escaflowne
- Excalibur
- Fatal Fury: The Motion Picture
- Final Fantasy 4,5,6,7,8,9,10,11,Tactics
- First Knight
- Grandia 1,2
- Lord of the Rings: FotR
- Lunar Silver Star Story, Eternal Blue
- Mask of Zorro
- Noir
- Ogre Battle
- Record of Lodoss War
- Suikoden 1,2,3
- Tactics Ogre
- Vagrant Story
- Waterworld
- Wild Arms 1,2,3
- Xenogears
- Xenosaga
As you can tell, I find video game (and movie) soundtracks to be rather appropriate for gaming...
Buying gamemusic CDs should be fairly easy - try out
www.gamemusic.com, for example (they might have Dracula: Nocturne in Moonlight). There are many other places as well.