In that order mother****ers. Those are some of the the top guys IMO (I haven't gotten a chance to really get into Richard Pryor, Lenny Bruce etc yet).
Others that I enjoy highly in no particular order:
Sean Rouse (actually, ANY of the Unbookables really)
Geoff Tate (local guy, but is really starting to make a name for himself):
There are plenty more. I'm going to be spending much time at local comedy clubs this summer.