I've mentioned a couple comedians in this list. But George Carlin has to be the best. Not only is he hilarious, but he's politically correct in his political incorrectness. He's right about everything. With Lenny Bruce too much before my time, George Carlin has to be the man.
I've embedded a few Youtube videos for your benefit. But here I'm going to do something better. First, here's a link to a list of some of his best quotes. Read. Enjoy. Next, here's a link to all of his videos. Watch everything. Laugh. Learn.