I'm a huge fan of both Grant Kirkhope (especially his Banjo scores) and Peter McConnell of Lucasarts/Double Fine fame.
No need for a Banjo music link here I guess but here's one of Connell's pieces for one of the best games of all time - Psychonauts:
I also love the orchestral Version of Death Metal band Dimmu Borgir that was used in Insanely Twisted Shadow Planet:
I also love the music of "Adventures of Shuggy" an Indy game developed by an ex-Rare staffer:
Brilliant, brilliant 2d platformer btw. Such a shame that it bombed badly commercially