Reply #19: Quite a few.

[ozymandius]

But then, I used to work in public radio. The partial list:

Van Cliburn - very cordial, energetic and quite flirtatious
Mark O'Connor - somewhat aloof when he was not 'on mic' but very friendly when 'off mic'
Gil Shaham - playful, witty, fun with a wisecracking sense of humor
John O'Conor - great interview, loved to play the piano while he spoke and extremely charming
Frederic Chiu - salt of the earth; he went wayyy out of his way to visit the radio station and a mental giant in music theory (computer science major in college), very devoted husband and father
Dmitri Hvorostovsky - Russian opera star; he was very friendly but shy in person and a very difficult interview despite being very comfortable in English
Sharon Isbin - just a joy to interview, always knew what she wanted to say and very playful; she would often call me when she planned to be nearby to schedule an interview; liked 'hanging out'
Konstantin Lifschitz: brilliant and completely flakey; he often has a weak anchor in this reality, speaking to a person; he can be in the middle of an answer and suddenly appear interrupted by a dust mote, fall silent and stare into empty space for long periods of time. His agent said that when this happens - the conversation is over.

There were many more artists I met. Only a couple were real jerks.