Wind Waker - All amazing songs, especially the Great Sea music.
Ocarina Of Time - Gerudo Valley is the best music ever put in a game.
Mass Effect Trilogy - Brilliant music, mainly Therum Battle, ME theme, Leaving Earth and An End Once & For All (which was the perfect music to end the trilogy and the 2nd best game song after Gerudo Valley).
Kid Icarus Uprising - Didn't expect it too have this amazing soundtrack, plus it comes with a music player so you can listen whenever you want!!
Sonic 2 - Great 16 bit music.
Sonic - Green Hill Zone enough said.
**Edit***
Final Fantasy 9 - Great music. Battle theme was great.