This lineup will surely date me. One interesting combo is I saw the Dead, The Band and the Allmans at the legendary Watkins Glen (upstate NY) concert, which was larger (people-wise) than Woodstock. It was a one day event, but the Dead played a multi-hour "sound check" the night before.
Of course, the show I saw in 1966 is a once in a lifetime deal, but hey, I was a lucky kid, what can I say (though I didn't hear a note of music that night).
This is NOT in chronological order (just in order of when the popped into my head)
The Beatles (Shea Stadium, 1966. I was 14. A rich girl's dad drove 5 of us to the show).
The Byrds
Santana
Simon & Garfunkel (reunion tour)
Grateful Dead (x4)
The Allman Brothers Band
J. Geils Band
Grand Funk Railroad
The Band
Dan Hicks and the Hot Licks (x7)
John McLaughlin and the Mahavishnu Orchestra (with Billy Cobham on drums)
James Taylor (x3)
Fleetwood Mac
Jethro Tull (x2)
Orleans (x5)
Harry Chapin
Loggins & Messina
The Rolling Stones (x2)
Some memory.
Southern Culture on the Skids
Livingston Taylor
The Who (circa 1968, the original Tommy tour)
The James Gang
The Eagles
Jackson Browne (he came on stage during an Orleans show in a small club in Syracuse, NY, circa 1972. Does that count?)
Bonnie Raitt
Karla Bonoff
Susan Werner
Michelle Branch (accompanied my teenage daughter)
The Academy Is, All-American Rejects, Rooney (another daughter show)
Dave Alvin
Asleep at the Wheel (x3)
Loudon Wainwright III (x6)
Yes
David Bromberg Band
Robbie Coltrane
Bob Marley & The Whalers
Stanley White
Bruce Springsteen and the E Street Band (x3)
Elvis Costello & The Attractions
Little Feat (with Lowell George)
The Beach Boys
Harry Connick Jr. (took the in-laws)
Hot Tuna
Richie Cole & Alto Madness
Smokey Robinson and the Miracles
The Temptations
Steely Dan
Taj Mahal (x2)
Three Dog Night (in high school, circa 1969-70)
Tom Rush
Peter Frampton
Traffic (with Steve Winwood, circa 1970)
Yo-Yo Ma
Man, that was some brain-wracking deal. But that's it. Not bad, all in all.
Edit: I was reading an earlier post, and I too saw Iron Butterfly in high school. Wow, that was interesting.