I've started using smart playlists in iTunes - they are rules that govern what kind of music is played instead of just picking a bunch of music. It self updates too.
So I have a mashups and fun smart playlists: house music, Girl Talk, Diablo Swing Orchestra, deadmau5 and skrillex among others.
A Triphop playlist: DJ Shadow, DJ Krush, Little People, BLockhead etc
A Chillax playlist: Bonobo, quantic, Nujabes (samurai champloo soundtrack etc) Matisyahu and Digitonal etc
it's working pretty well so far