Halo: Combat Evolved (musical score)

For me, the Halo: Combat Evolved musical score is one of the best game sound tracks out there.

Martin O'Donnell is genius, and bang-for-the-buck wise, this is a way better value than the Halo 2 score (which rocks on its own, but has far fewer orchestral pieces).

And it just takes me back to the game that got me to buy the Xbox in the first place ...