If I put on an elliott smith album, and THEN start smoking bongs, I will get to about 3-4 bongs before I forget about weed and just start singing and pounding my fists on the desk. Then I start feeling real down... then I smoke more... rinse/repeat.
I'll listen to just about anything in my iTunes library when I'm stoned, but there are a few albums and groups that sound particularly epic after some major tokage.
Sleep - Dopesmoker (of course)
Beastie Boys - Paul's Botique
Dr. Dre - The Chronic (this is a must for any self-respecting pothead)
My Bloody Valentine - Loveless
Bob Marley (obvious)
Cypress Hill (obvious)
Animal Collective
DJ Shadow - Endtroducing...
Jimi Hendrix