I would agree that Jesper Kyd has some good music from Hitman.

Also like th Command and conquer soundtracks especially the new one, Red Alert 3. Thought it was excellent.
Other good game soundtracks would be the music from:
World in Conflict, really suited the game.
Operation flashpoint had good rock music
Crysis good stuff on it too
War of the Worlds game soundtrack was amazing
Halo 3 bought the album to it
Quake II a classic, but all good ;)
Incoming forces, good dance music
The radios on the GTA games were alright