Ke$ha: once. I had another opportunity six months before, but various circumstances prevented me from going. I also had an opportunity in mid-2010, but wasn’t that big of a fan quite yet.
So far, I have seen my most favorite singer James Otto two times: June 11, 2008 and January 31, 2011. 
God bless you and him always!!!
Holly
P.S. I pray that I am able to see him again soon!
Jack White, 17 times.
Well, to be accurate -
The White Stripes 8 times
The Raconteurs 6 times
The Dead Weather 1 time
Jack White 2 times
For one of my other obsessions, I saw Pink Floyd doing The Wall in 1981. I saw Roger Waters doing The Wall in 2011, and will see him doing the same twice this year.
Frank Zappa five times.
King Crimson at least eight times, plus a couple of ProjeKct shows, but never in their peak period in the '70s.
Jethro Tull at least 24 or 25 times, but not recently.
My daughter – 5’3", slim, hazel eyes, dishwater blonde hair? ring a bell? 
– was probably in the audience with you a couple times. She’s seen him eight times, and all but one involved out of state travel.
For me, Jimmie Dale Gilmore – three times, twice with the Flatlanders, once solo. He’s the only act that I’ll travel more than 100 miles for.
Jimmy Buffett, three times, all in the PPH days so probably never again.
Aerosmith, 5 times. The first 3 were all while they toured for their first album, again in 1979 then last year on their last tour.
Hell, I forgot about Jimmy. Another one that is up in the dozens, since the days when it was just Jimmy and Fingers out on tour. Proto-Reefers, if you will. Before tail-gating, before the Parrot-Heads even knew what tequila was.
Sonic Youth- twice. Once at Lollapalooza (94?), and again shortly thereafter at the Metro in Chicago.
Prince- never.
“Weird Al” Yankovic- twice. Once as a kid at the Indiana State Fairgrounds, and again a few years ago at the Indianapolis White River Amphitheater.
Jucifer- once. Just happened to run across a flyer on the same day that they were playing here in Indianapolis, so it was a complete surprise. Small club called Radio Radio. Such a small place and they had so many amps that to hear the music, you had to go out to the sidewalk.
I’ve seen my favorite local band, Junior Doctor, twice, once at Warped when they were added unannounced to the local show and I didn’t know they were playing till I got there, I had to follow the signs to find them.
Also apropos, once I saw The Warlocks (link because there are probably several bands called that) open for The Black Angels (another link for disambiguation) in a small club, and both groups played very loud. The Warlocks were good, and again were very loud, but still listenable.
The Black Angels pegged the hairs in my ears so that I literally couldn’t hear any louder. It all sounded flat. I left after one song and am not sure that staying for those couple of minutes didn’t cost me some of my hearing. (I don’t wear earplugs at shows because what’s the point? Bands usually don’t hurt. But then again maybe I should, not because of the bands but because of fans screaming in my ear. I’ve gone away from many a concert with only one ear ringing for a couple of days because that was the ear that one fan screamed into from less than a foot’s distance.)
Pink Floyd- 3 times.
Roy Buchanan- 3 times.
Stevie Ray Vaughan- 11 times.
Bela Fleck & the Flecktones- 12 or 13 times.
Bela Fleck in other projects- at least 8 or 10 more times.
Edit: my username is a Flecktones tune
Eight times for Alice Cooper plus meeting him at a record signing in 2010. The most recent was in November.
Hi Faithfool!
ELO: I missed two opportunities to see them:
- In 1981, I was 16, and my friend and I (both big ELO fans) couldn’t convince our parents to let us drive 2 hours from our home in Green Bay to Milwaukee for their concert.
- In 2001, Jeff Lynne was set to tour with a new version of the band, and my wife and I eagerly got tickets. The tour was cancelled before it started, due to weak ticket sales; as it turned out, we probably wouldn’t have seen them, even if the tour had gone on, as the concert date was to have been September 12th, 2001.
Queen: never got the chance to see them.
Yes: have seen them twice, in 1984, and again in 2008.
Grateful Dead w/ Jerry 87 times including the LAST 6 shows he did.
Other incarnations of the dead family 25-30 times
Leftover Salmon 20+/- times including cooking for them on a few gigs.
John Hartford 6 times.
Little Feat w/ Lowel 3 times…w/o Lowel 6ish.
That really sucks.
I only saw them once, but it was a doozy. It was the Out of the Blue tour with the giant spaceship. What was especially cool was that I was working selling T-shirts at the arena during that period with my mom and older brother. So we got there hours early, which meant that we got to see them putting the whole thing together and doing the sound check. It was a groundbreaking tour for two reasons - it was the first time a tour “flew” a sound system (they had big cages to hold the speakers) and the first time they moved the lighting rig while the stage was occupied. They had invented a new type of synchronized hoist that is the standard now.
The same job let me see Yes on the Tormato with the rotating stage. Very cool.
Sounds awesome to see. I have a DVD of a concert from that tour. 
Rush - 53 times since 1983.
Here are a few of many.
Kate Bush - I became a fan after she stopped performing, sigh, but I met her in 1985 (swoon). I was there in 1990 when she sang a short song live and gave a speech to fans, and I was there in 1994 when she gave another speech to fans (no singing this time).
Happy Rhodes - 24 separate live shows (though many times she’d play 2 shows in one night). Only 2 of the shows were in Chicago. One was in Kenosha, one was in Toledo, and the rest of them were on the East Coast (Philadelphia, New York City, Troy and Albany, NY).
Genesis - 10 times, I believe, including the Selling England By The Pound and The Lamb Lies Down On Broadway tours with Peter Gabriel. I haven’t seen them live since 1983.
Peter Gabriel - Probably 6 or 7 solo shows, I can’t remember. I don’t see him live anymore but it’s because his shows are way too expensive now.
Tori Amos - 10 or so, maybe more. I don’t remember either, but my favorite will always be her first tour to support Little Earthquakes. The room (Schubas) is a tiny place, holds maybe 100-150 people. She had a borrowed electric keyboard that kept messing up on her, and she’d have to crawl down underneath it to fix the pedals. It was a great show anyway.
Rev. Peyton’s Big Damn Band - God, who knows? A couple dozen at least. Every show is pretty much the same but such great fun it’s worth experiencing over and over just to have a good time.
Sarah McLachlan and Jane Siberry - several each, I don’t remember.
Imogen Heap - 3 times.
Victoria Williams - at least 5-6 times.
Warren Zevon-Once in 1991. (Ludovic, The Odds were the opening act and Zevon’s backing band for the tour.)
REM-Four times between 1985 and 2003.
U2-Once, Zoo TV in 1992.
Morphine-Twice.
The White Stripes.
9 times in three continents (within 1 year!).