Your top 3 comedians

Charlie Chaplin is always #1.
Other two are Ed Murphy and Martin Lawrence...

richard pryor, george carlin, bill hicks......back up...bob newhart, steve martin, martin mull

I'm going to stay away from the classics, as most kind of go without saying, and are probably nothing new to anyone (I like'em as much as anyone else - how could you not). I'd rather list some more contemporaries who consistently impress me when I can catch my breath from laughing so hard.

Mitch Hedberg (RIP)
Lewis Black
Stephen Wright (OK, he's timeless, classic in his right... so I'll add one more)
Amy Sedaris (doesn't do standup, but love her humor)

Marco

John Belushi
Phil Hartman
Jack Black

These guys aren't really stand up comedians... just guys who make me laugh every time I see them. I would have to put Richard Prior and Johnny Carson on the list of most beloved.

Modern:
Brian Regan
Jon Stewart

Classic:
Groucho Marx