I agree with Cross, Chappelle, Stewart, L.Black and Maher being funny. I wanted to add a few people I think are hilarious but no one has mentioned yet:
Eddie Izzard (check out Dressed to Kill)
Carlos Mencia (Take a Joke America is a must)
John Leguizamo (his one man shows like Freak are great)
Steven Wright (dryly tells one-liners that are hysterical)
Stephen Lynch is a pisser. I think Ray Romano is one of the least funniest guys of all time and his show is an absolute abortion. Dennis Miller has never been funny and never will be. Same thing goes for Richard Lewis. Reno 911 is real funny...
One guy on the list who you didn't mention who I find very funny is Denis Leary especially since I've fallen in love with Rescue Me.
Adam Sandler is SOOOOOOOOOOOOOOOO overrated. You could pull any schmuck of the street and he could do what sandler does. I enjoy his movies because of the script, not him. I bet at least half the cafe is as talented as him, and could do what he does. He doesnt bring anything special.