My photo of him turned out a bit weird. But indeed, very nice guy.
I lucked into back stage passes for Styx (please see user name) and I was pretty happy I had some intelligent questions to ask them. It’s not like I thought beforehand “best have something ready to say just in case!”, it was more that when the opportunity presented itself I was able to actually have a short but good conversation apart from “hey, love your stuff.”
This particular meet & greet was one for industry types so it wasn’t a conga line going past them as they sat behind a table signing autographs, it was folks milling about and talking with them… like I said, I lucked into a somewhat unique situation.
It was great, they were great, and Tommy Shaw has insanely gorgeous blue eyes… he really seems to pay attention to whomever he’s talking to for those few seconds, so I got to take a nice close look. 
Alan Rickman has been my favorite actor since I saw him in Die Hard when it came out. I finally got to meet him last spring when I was in New York. He was charming and affable. Exactly as you’d expect.
Although I’ve never met my favorite musical artist (Pete Townshend), I did meet his brother Simon after a gig in San Francisco. Really nice guy who loves to hang out with the fans. After chatting with him a bit I wished him well and headed out the door; he raised his hand and shouted a hearty “Thanks for coming out!”
Guess I’ll have to alphabetize this:
Truman Capote
Billy Crystal
Allen Ginsberg
Larry Kramer
Cubby O’Brien
Bernadette Peters
Ayn Rand
Stephen Sondheim
Mickey Spillane
Barbra Streisand
Nope.
Sure, I have a list in the hundreds & it probably changes daily a little bit. People from Film & TV & Music & Politics. I’ve just never been in the right place at the right time to meet any of them though.
That and lets face it: There’s Just No Way I make a good enough impression to make anyone curious on the other end.
I found out my favorite football player, John Hannah, was going to be at a charitable golf tournament so I bought a ticket so I could meet him, but he was a no show. I shrugged it off, but my wife was livid. A family friend, who works in the same investment firm, informed my wife that the no-show was due to a bad case of gout. Unbeknownst to me, my wife had the family friend deliver a letter to Hannah, basically ripping him a new one and questioning his manhood over his inability to keep his obligation to show up at the tournament. Hannah, upon reading my wife’s diatribe, felt bad and arranged for me to meet him before he was to speak at our town’s financial meeting (his firm works on our town’s investments). Turned out to be a real cool guy.
Did you turn your back on him?
Work allows (forces?) me to do such things. I work in media, used to work in sports media. It allowed me to meet Tim Duncan several times and It pleased me that he was very nice as he is my favorite athlete. I liked Pop as well, he was friendly.
As for musicians, I’m a classical guy so, no, but I’ve met a ton of musicians and Great big sea is a band I quite like, I’ve met them. We got drunk together. Loved Our Lady Peace as a younger man and met them at a concert I worked on a few years back. Very nice. Barenaked ladies as well.
I met the Coen brothers by chance at TIFF a couple years back. Frances Mcdormand was there as well. They were friendly and chatty, I was a blabbering fool.
I met Alice Cooper at a record signing in Vancouver. I brought along my best souviner, a big stuffed chicken feather from a dancing chicken costume circa 1979. He said “hey, I married one of those chickens!”
When I was a teenager in the 80s, I was a huge fan of the band Kansas (even though their glory days were in the 70s). I met a couple of members of the band at a Christian music festival in 1985, when they were performing with a band called A.D. Very nice guys.
One of my favorite jazz pianists lives here in Seattle, and about a year ago I bought a keyboard, screwed up my courage, and emailed her to ask for lessons. Now I see her every few weeks and disappoint her with my lack of progress. 
There are certain advantages to following tiny, obscure bands. Slim Cessna’s Auto Club is one of my faves, and I shared a couple cigarettes with Slim at a show in Cincinnati.
(Separately, there’s an outside chance that I was at that show in the video: It looks like the Lion’s Lair in Denver, where they did their 20th anniversary shows. I was there, having a minor nervous breakdown. :P)
I met my second favorite rapper, Rakim, when I was 10. I was so star struck, all I could say is, “Can I touch your chain?” which was the dumbest thing ever. He said, “yeah,” and I lifted the huge gold rope and thought to myself how much lighter it was than I thought it would be. Then his deejay said, “That’s enough, move it, get off the damn bus” and I hated his deejay since then. Meanie.
When I was a kid in elementary school, I was a huge fan of Louis L’Amour (the western writer), and was on an obsessive quest to collect and read all 110 of his books (or however many there were), which was a huge task back before the intarwebs, involving endless hours scouring obscure bookstore shelves. Anyhow, I finally got to attend a book signing of his when I was 11 or 12, and got my picture taken with him, which I framed and put on my bookshelf. Good times, for a budding nerd.
I’ve mentioned before that I met and spoke with Dave Brubeck. Nice guy, very humble and personable.
I have been lucky enough to have a few jobs where I got to meet hundreds of big name celebrities, far too numerous to mention.
Some I got to speak/work with and get to know better, others just an short introduction.
The vast majority were nice, normal people - away from the fans and hoopla. A few were arrogant jerks, and a few were exceptional individuals who almost seemed destined to have become who they were.
When I worked at Borders corporate HQ, I sometimes went to author dinners within the SF genre, as I was the copywriter for the genre. Two stand out, and oddly they took place the same week.
Neal Stephenson, was a boring sulky douchebag. Worst author dinner I ever attended, he didn’t say 10 words to us… I ordered dessert just to spite him. It was a cappuccino creme brûlée.
Terry Pratchett, on the other hand, was one of the most delightful people I’ve ever had the pleasure to share a meal with, and I count that evening among my most treasured memories.
Back in the 60s, there was a local band in Houston that was hotter than firecrackers, Neal Ford and the Fanatics. They knocked the Beatles out of the #1 spot on the local top 40 for a while. I met them several times.
I got to spend time between sets with the late Michael Hedges during a show at the old Rockefeller’s in Houston, talking about music in general and guitars in particular. A very, very nice guy and his death was a tragic loss.
Dave Nachmanoff is Al Stewart’s lead guitar player whenever possible. I got to meet both of them last year when they played Houston, and it turns out that Dave went to college with my sister-in-law and she sang backing vocals on one of his early recordings. Dave and I struck up a friendship and he’s sent me music for several of his original songs. And I played one of his songs for her (with a slight modification) when SWMBO and I tied the knot last April.
Congratulations on the Ke$ha thing. Sounds like quite an opportunity since it’s not like some artists who are play small venues and hang around after the show, etc.
A favorite musician of mine is Mary Fahl (formerly of October Project). My wife and I first started talking online when I recommended an October Project song to her and she started asking me about other music. So when Mary Fahl was playing a show near her, it seemed like kismet to make it the basis of our first in-person date. After the show, Mary stayed around and we got to talk to her and told her it was our first date. She laughed and predicted that we’d get married.
Five or six years later, Mary Fahl was playing in Chicago and we saw her again. She stuck around again and we got the chance to speak to her again and told her of her earlier prediction and that now my wife was pregnant with our first baby. She congratulated and hugged us and wished us well.
As for “knowing” someone ruining their work if the person is a jerk, we lucked out. Despite her very atmospheric, moody music she was a very bright, humorous person in “real life” and fun to watch perform and to speak with. You might expect her to be all dark or somber but she was completely the opposite.
A few of them. Met Bob Mould (Husker Du) a few times, and even sang “Celebrated Summer” onstage with him once. He’s cool and easy to talk to.
Met The Replacements after a show in the '80s - they were all cool, too, except Paul Westerberg (who I met again a decade later), who was kind of a dick.
I also got to go backstage at a Rush concert in 2011 and hang out with Geddy and Alex for an hour or so (no Neil, sadly). They were super nice and easy-going.
ETA: Oh, also Robyn Hitchcock. Very friendly.