I enjoy the humor of Chris Rock, Ron White, and Kathy Griffin. I think as far as straight stand-up goes, they are three of the very best that are still out there doing their thing.
Overall, however, when I think of "funniest" people I think of who makes me laugh on a daily basis, be it on radio or TV. In that group I have to say Howard Stern is one of the quickest wits out there. When Artie Lange was on Stern's show, he was also one of those "funniest" people. On TV, Jerry Seinfeld and Larry David are two of my old favorites. SOOOO witty!