Zelda: A Link Between Worlds:
'Hilda's theme': http://www.youtube.com/watch?v=OrrgER0PK3Q
'Yuga Battle Theme': http://www.youtube.com/watch?v=Oxl-n80bq_Y
No More Heroes 2:
'Philistine': http://www.youtube.com/watch?v=CYjYCaqshjE
Pandora's Tower:
'Masters of Dusk and Dawn': http://www.youtube.com/watch?v=R1nMbFpBsTo
and the credit music from Descent 2 was amazing, as was the ingame Redbook music. It was the first game I played with real studio recorded music and not MIDI crap. It was done by Type O Negative, and was just sublime and probably what got me into metal music.
The full Descent 2 music listing:
https://www.youtube.com/watch?v=ksPiXWw-SRE&list=PL2ABAB19080A2CA68
Over World Night, from Terraria. The video doesn't have the best sound quality, but the music is still pretty awesome. Terraria is a great example of how you don't need a massive studio to make an awesome soundtrack for your game, I absolutely love it.