well, it depends on what you like.
hip hop: immortal technique, canibus, jedi mind tricks, kanye west, talib kweli, handsome boy modelling school, madvillainy, edan
rap: jay-z, rza (of wu-tang), de la soul, obie trice
adult contemp: fiona apple, roni gellert, theresa sokyrka, aimee mann, ray lamontagne, bright eyes, ben folds
metal: trivium, darkest hour, as i lay dying, buried inside, unearth
indie: cursive, and you will know us by the trail of dead, dredg, xiu xiu
ambient: m83, moby, sigur ros, enya, zero 7, frou frou/imogen heap
alt. rock: weezer, phantom planet, low millions (leonard cohen's son's band)
instrumental: explosions in the sky, daniel langois' new album, grace cathedral park, godspeed you! black emperor
the only thing i can't speak for is country, i guess...i don't think it's fallen off at all