In no particular order...
Tom Petty and the Heartbreakers - Sep 22, 1991 - Into The Great Wide Open Tour
Springsteen - Jan 20, 1981 - The River Tour (just under FIVE HOURS)
Stones - Dec 3, 1989 - Steel Wheels Tour
Deep Purple - Apr 1st, 1985 - Perfect Strangers Tour
The Who - Oct 9, 1982 - It's Hard Tour
Steppenwolf (with a relatively unknown Stevie Ray Vaughan opening) - CNE Grandstand
Neil Young - Feb 18, 1983 - Solo Trans Tour
Lou Reed - Late '80s - New York Tour
Eric Clapton - June 21, 1985 - Behind The Sun Tour
John Cougar Mellencamp - Lonesome Jubilee Tour
U2 - The Oshawa Tree Tour
R.E.M. - The Green Tour
The Black Crowes - Free Concert - G. Ross Lord Park, Toronto
Gregg Allman - Nag's Head North Bar, Toronto(walking distance from my parent's house. As I left after the show, I saw Gregg by himself smoking a cigarette in the outdoor tunnel that connected the bar to the patio. I boldly staggered up to him and said,
mapleleaf : "Great show man."
Gregg : "Thanks man. I'm taking contributions for tokes."
mapleleaf : "Awww sorry man, I'm all out or I would for sure. Hey, would you mind autographing my cigarette pack for me?"
Gregg : " No problem man."
...then I said thanks and goodbye blah blah blah.
How cool was that? It would have been cooler if I actually had a doob for him, but whatever. Gregg Allman asked me for drugs.