Greatest standup comedian of all time?

I don't know if he was considered a stand up comedien, but Groucho Marx was the funniest man to ever live. Richard Pryor second.

perhaps a little too corny for this forum ?
i enjoyed VICTOR BORGE'S antics - saw him live a couple of times -
he certaily made me laugh !

here he is with DEAN MARTIN doing PHONETIC SPELLING .

http://www.youtube.com/watch?v=N7L02tCNi0I

I can't believe that no one mentioned Bill Cosby, the man is a comic genius. I would say that he is in fact the best of all time.