Let's also remember he was in "I'm Gonna Git You Sucka" (in a scene with young Chris Rock) as well as the singer of the "Shaft" theme song AND the "Beavis and Butt-Head Do America" theme song. Sadly though, he was a scientologist so slightly batty. I really liked the guy but hated his affiliation with the Church of Scientology which promted him to quit Southpark (he was willing to mock every religion except his own) but I heard he later returned.
Sad, but I'm sure Southpark will retire the character Chef, how would you replace such a classic role (and Voice).