ok, i believe that the soundtrack often makes a game just as much as the gameplay does.
some notable examples are:
Universe at War: Earth Assault
C&C Generals/Zero Hour
Scott Pilgrim vs the World: The Game
Legend of Zelda: Ocarina of Time
Total Annihilation (or actually, anything made by Jeremy Soule)
All of the Fable games (I, II, and III)
and Constellus
it would take so much time (and bandwidth) to show you guys all of that music, so im going to tell you to go to Youtube and look them up yourself