I saw Chris Rock on some television show a while back talking about how no one believes he's 42. Had I not heard it straight from the horse's mouth - and double-checked against imdb in case he was just having fun - I wouldn't have believed it either. It would seem no matter how old Rock gets, he will forever remain in his early-thirties...I could think of worst fates.
Rock's in my top-ten for one reason - the Gun/Bullet Control routine, probably the funniest and most spot-on piece of stand-up comedy ever documented on film. Without that bit, he would probably hover around the number 11 or 12 spots. Would I pay to go see him? Repeatedly. Other than the Gun/Bullet Control piece do I recall parts of his act while walking down the street and break into spontaneous laughter? Not as much as some of the others on this list.