i don't think anyone becomes famous unless they are prepared to be a jerk and i think it's safe to assume that any famous person, philosopher or not, is a jerk until proven otherwise.

that said, the most famous living philosopher i can think of whose work i have enjoyed reading and who at least kinda seems like not a jerk is probably Harry Frankfurt. although i don't know him personally and would not be surprised to find out he's actually a jerk. he did go on the Daily Show, after all.