Louis CK is an interesting example of an artist who has grown. His stuff from 20 years ago (that I've seen, at least) was really bad; it was timid and boxed in by convention, which is death to comedy. Somewhere along the way he obviously said fuck it and started telling the truth more directly and provocatively. And that is how lead is transmuted into gold. Funniness is almost a side effect.

Now he seems closer than anyone working in this area to Lenny Bruce and Bill Hicks territory (if anybody's closer, I'd love to hear about them) with at least a shot at equalling them, which would be amazing.