First one - Grand Funk and Wet Willie - March 1974 at Tampa Stadium.
After that, a lot of it's a blur

but here's at least a partial list:
Crosby, Stills,Nash, & Young w/Jesse Colin Young - August 1974
Lynyrd Skynyrd, Charlie Daniels, Outlaws - July 74
Marshall Tucker Band (many times)
Atlanta Rythym Section (many times)
Tampa Jam - Atlanta Rythym Section, Pure Prarie League, Kiss, Dr. John, War, Marshall Tucker, ZZ Top, Johnny Winter
Yes and Griffin
Savoy Brown
Foghat
Peter Frampton & Gary Wright
Ten Years After, Leslie West, & Gary Wright
Stones, J. Geils Band, Rufus, & Atlanta Rythym Section
Allman Brothers, Grinderswitch, 38 Special
Bruce Springsteen (in a 400 seat theater for $4!)
Johnny & Edgar Winter together!
Southern Jam - Marshall Tucker, Lynyrd Skynyrd, Charlie Daniels Band, Bonnie Raitt, others...
Boston
Rush
John Mayall and Leslie West
Lynyrd Skynyrd, four days before the plane crash - we saw the second night of the Street Survivors Tour, and they only played four
Heart
Led Zeppelin - June of 1977* They played three songs before a monster thunderstorm soaked the stage. It wasn't safe for them to continue, so they said they'd replay it the next night. Idiot fans caused a riot causing the Tampa city council to cancel the replay (and all concerts at Tampa Stadium for a long time). I bought tickets for a show later in the tour that was to be held in the Superdome in New Orleans, confident that weather could not be an issue. Four days before the show lead singer Robert Plant's young son died in England, and the band returned home, cancelling the rest of the tour. I've had Led Zeppelin tickets four different times, but have only seen them play live for that shortened set in Tampa - The Song Remains the Same, Celebration Day, and Nobody's Fault But Mine.
Blue Oyster Cult
Some festival type concert at Peppin Rood Stadium in Tampa - I remember Seals & Croft, Alvin Lee, Joe Cocker, and some other acts I don't remember (including the headliner!)
Aerosmith and Mahogany Rush (they were drunk and/or the sound system sucked - I've never been more disappointed in a show - at least not at a full one!)
Ted Nugent, Golden Earring
Sea Level, Joe Cocker, and others...
Johnny Winter playing "Nuthin' But the Blues"
Frank Zappa
Kansas & Styx
Styx & UFO
Earl Scruggs Revue & Mac Wiseman
Fleetwood Mac
Beach Boys
REO Speedwagon
Head East
Stevie Ray Vaughan - twice at Brassy's - a nightclub in Cocoa Beach
Hank Williams Jr. - also on two different occasions at Brassy's - once with a very traditional country crowd and once with an "Outlaw Country" crowd.
Robin Trower
Pink Floyd - once in Tampa, once in Orlando
U2 & The Alarm (at the Orlando Jai-alai fronton!)
Fabulous Thunderbirds
Nighthawks
The Who, Joan Jett, B-52s
Rolling Stones, Living Colour, Rockets (1989 Steel Wheels tour)
Eric Clapton
BB King
Buddy Guy
Lee Ritenour - several times - the best was in a little club in Seattle called Jazz Alley, and Eric Marienthal was playing sax with the band that night!
Spyro Gyra
Yellowjackets
Bob Seger, Molly Hatchet, Rockets
ZZ Top, Rossington-Collins Band, Pat Travers Band, 38 Special
Peter Frampton, Kansas, Derringer
Florrida World Music Festival - Ted Nugent, Aerosmith, Cheap Trick, Brownsville, Blackfoot, Mahogany Rush (this time Aerosmith - whether sober or just motivated because Nugent got top billing, ROCKED! Now I could see what the hype about seeing them live was all about)
The Who "Farewell" Tour
Stevie Winwood
Neil Young - saw him and Crazy Horse play at the Costa Mesa Ampitheatre in Orange County, CA, - and with the International Harvesters in Gainesville, Fl, a one man show on the "Trans" tour in the brand new Sun Dome on the USF campus in Tampa, then back with Crazy Horse (the 3rd best garage band in the world) in Daytona!
R.E.M.
Springsteen on the "Born In The USA" tour with 80,000 of my closest friends in the Orange Bowl in Miami on a weeknight - there's a great story about that trip that I can laugh about - now!
Styx and Kansas - this was a kind of reunion tour. Both bands had their original casts, but boy did they show their age. Leslie & I had seen the tour they were on together in 1978 - but I saw them in Lakeland, Fl and she saw them in Rochester, NY - and it was 10 years before we'd met. So we had a good time seeing them together while reminiscing seperately!
Paul McCartney - sort of! I got to go to the Super Bowl where he performed at halftime!
I'm sure that there are a lot more that I can't remember right now. Some of the more notable bands I have never seen live that I should have:
Jimmy Buffet - I can't believe this one
Eagles
Tom Petty
What a fun thread!