Louis CK is awesome. It still amazes me that so many people recently discover him and his work. Not everyone is into stand-up at the same points in life, so clearly I don't expect him to be some household name, but really, he should be. He's the best comic in the world right now IMO, better than prime Seinfeld(who as a comic, is not as good as a general entertainer IMO).
Aside from obvious names that people talk about in these topics often: Bill Bailey is a guy that I really like. He's maybe the best PG comedian, and I don't think he tries to be clean, it's just that he's wired a different way.
My all time favorite is Robin Williams. But not everyone likes Robin Williams, and his last 20 years have been weaksauce compared to his first 10. Going from comedian to actor back to comedian is tricky in itself. George Carlin was a friend of the family, I met him a few times when I was very little and he was great around kids like myself. Maybe my first experience to being around another open anarchist, and might have made me rethink some things at a younger age. It wasn't until I was older, that I knew who he was and heard his comedy. I love his work, it's pure genius. One of a kind. But I still see the guy that I knew when I was little, which might cloud my judgment a bit.