Favourite games with music:
[*]Bandits: Phoenix Rising - It's just so catchy and energetic!
[*]MechWarrior 2 - I used to listen to that on the way to school.
[*]Descent ][ - Ditto.
[*]Project Nomads - Very tribal. Fits the mood perfectly.
[*]Divine Divinity - But of course! Beautiful sounds which don't get in the way.

The music needs to be atmosphere, but without interrupting the game. I remember in Space Colony, I though some of the music was actually warning sounds and started getting concerned as to what was happening. The game should tak precidence, with the music enhancing it. It should just be a game with some music. I've got WinAMP for that.