Classic Rock is, obviously, good music when you're high. I especially like The Doors, one of my favorite classic rock bands. Pink Floyd is very good to chill to, and Led Zeppelin is good if you're feeling more active or driving around. Also, Fly Like An Eagle by the Steve Miller Band is a pretty amazing song.

For more contemporary stuff, Gorillaz is a very good band to listen to. Lots of very original songs. I also like the band Mindless Self Indulgence, if anyone's heard of them, their music often has many different things going on at once, and you can hear them all better when you're high.

I'm also partial to jazz/big band music when I'm high, but I enjoy playing it more than listening to it when high or not high ^^ Nothing like going to band/jazz band class stoned, it's pretty amazing.