Metal - Opeth, pantera, arch enemy, katatonia, Sabbath, Bodom, Dimmu, death, etc
Rock - Floyd, Soundgarden, Smashing pumkins, clapton, foo fighters, chilli peppers, skynyrd, etc
Jazz - Coltrane, Cannonbal Adderly, Charlie Parker, Count basie, Miles Davis, etc
Hip hop - The Roots, Talib Kweli, Mos Def, Tribe, Hiroglyphics (I know thats misspelled), Wu-tang, del, Jedi Mind Tricks, Immortal technique etc.
Jam - Phish, Dead, Martin Sexton, Umphrey's Mcgee, Younder Mountain String Band (not sure if this really fits but oh well), etc

When I'm stoned I usually dig on the jam stuff, some of the chiller Hip-hop stuff, floyd, and Opeth has some really chill atmospheric stuff thats is AMAZING when your blazed. I highly recommend everyone check out their damnation album and listen to it when your high, especially with a good system.