I've personally met enough of 'em, too, not to be impressed by 'em, as John has been a frequent guest at sci-fi conventions where they've also invited actors from teeevee and movies. One, though, impressed me: Mark Goddard, who played the role of Major Don West in the original *Lost in Space* teevee series. Mark switched careers later in life and got his degree in education, and then went on to teach troubled teens. Mark Goddard not only had a few cool jobs in his life, he's also a cool person.
And then there are the celebs I've met at literary "do's", who have been absolutely fascinating. Joseph Heller (may he rest in peace) was one of the most intriguing and charming.