I think I saw the episode of City Confidential about Chuck’s dinner companion!
Anyway, to answer the question, the famous people I’ve met have all been authors.
I didn’t get to talk to China Miéville long enough to form an opinion beyond, “Hey, he’s pretty cute in person…”
I hate to speak ill of the dead, but Robert Jordan struck me as self-absorbed and snobby.
If you read Neil Gaiman‘s blog (which can be found here in case you don’t read it yet and would like to), you’ll be happy to know that he represents himself very well and is exactly the same in person. I spent about fifteen or twenty minutes talking to him at the 2004 WorldCon and it took all my strength to keep from turning into a squeeing mass of pathetic fanbrat. He was so humble and soft-spoken and funny. He really seems like such a fantastically nice guy.
The year before that, also at the WorldCon, Terry Pratchett gave me a very yummy peanut butter cookie. I didn’t get to talk to him for very long—it was after a book signing and I was helping clean up the area for the next panel—but anybody who gives me cookies and thanks me for helping out is a-okay in my book. I hadn’t read anything of his before that, except for his collaboration with Neil, but he was so nice to me that I went out and bought seven Discworld books which I ended up loving.
George R.R. Martin is one of the best people I’ve ever met. His partner, Paris McBride, is also a completely awesome example of humanity. I’m so glad that he became a writer and that someone steered me toward his books, or I never would have gotten the chance to meet him. If he never wrote another word I’d be pretty upset because his stuff rocks but I wouldn’t complain and I wouldn’t stop singing his praises. He’s so friendly and funny and snuggly. And he has good taste in booze. (He got me hooked on Bailey’s.)
I met both Gardner Dozois (former editor of Asimov’s Science Fiction magazine) and Howard Waldrop through George. Neither meeting was long enough to get a really solid opinion. They both seemed nice and Gardner in particular made me laugh a bit.
Also, I’ve never met them in person, but I’ve corresponded one-on-one with both Anne Rice and Poppy Z. Brite. Both of them are jerks. But Poppy is a jerk in an oddly endearing way. Anne Rice is just… a jerk.