Ok, I gave my list a shot. There are certainly a ton I've missed, and it should go without saying that I've seen several of these more than once, some many more than once.
Jefferson Airplane
Jefferson Starship
Hot Tuna
Jorma Kaukonen
The Grateful Dead
The Doors
Bob Dylan
Dylan with The Band
The Band
Arlo Guthrie
Rolling Stones
B.B. King
Albert King
The Kinks
John Mayall & The Bluesbreakers
Traffic
Spirit
Jimi Hendrix Experience
Band of Gypsies
The Guess Who
Peter, Paul and Mary
Santana
Joni Mitchell
Simon & Garfunkel
Paul Simon
Tom Waits
American Dream
Aum
Booker T. & The M.G.s
Tim Buckley
Paul Butterfield Blues Band
The Byrds
Canned Heat
The Chambers Brothers
Chicago Transit Authority
Joe Cocker
The Crazy World Of Arthur Brown
Creedence Clearwater Revival
Crosby, Stills & Nash
Crosby, Stills, Nash & Young
Neil Young
Steven Stills
Dr. John the Night Tripper
Dr. John
Iron Butterfly
Janis Joplin
Pacific Gas & Electric
Little Richard
Lothar and the Hand People
Hugh Masekela
Buddy Miles
Laura Nyro
John Gorka
Frank Zappa
The Mothers Of Invention
Tracy Nelson & Mother Earth
Procol Harum
Buddy Rich
Captain Beefheart
Sir Douglas Quintet
Three Dog Night
Johnny Winter
Bruce Springsteen & the E Street Band
Bruce Springsteen
Southside Johnny and the Asbury Jukes
Christine Lavin
Van Morrison
Jesse Colin Young
Tom Scott and the L.A. Express
The Moody Blues
Judy Collins
Led Zeppelin
Country Joe & The Fish
Sun Ra & The Astral Arkestra
Leo Kottke
JJ Cale
Alan Stillwell
Jackson Browne (who thought he knew me!)
David Bromberg and his Big Band
Greg Brown
Guy Clark
Shawn Colvin
Iris Dement
Ani DiFranco
Creedence Clearwater Revival
John Fogerty
Steve Goodman
Nanci Griffith
Arlo Guthrie
Robert Earl Keen
Allison Krause
Patti Larkin
Taj Mahal
Melanie
Bill Morrissey
Randy Newman
Tom Paxton
Utah Phillips
John Prine
Lou Reed
Bonnie Raitt
Jonathan Richman & The Modern Lovers
Tom Rush
John Sebastian
Michelle Shocked
Ricky Skaggs
Patti Smith
Chris Smither
James Taylor
Livingston Taylor
Dave Van Ronk
Townes Van Zandt
Loudon Wainwright III
Rufus Wainwright
Jerry Jeff Walker
Jill Sobule
Doc Watson
David Wilcox
Dar Williams
David Wilcox
Brooks Williams
Dar Williams
Lucinda Williams
Buffy Sainte-Marie
Kate Bush
The Kinks
Rickie Lee Jones
Donovan
Richard Thompson
Richard and Linda Thompson
The Animals
Eric Burdon
Smokey Robinson
The Soul Survivors
Jackie Wilson
Captain Cody and The Lost Planet Airmen
Otis Redding
Procul Harem
The Who
The Steve Miller Band
Ten Years After
Mitch Ryder & The Detroit Wheels
The Mamas & The Papas
Electric Flag
Bruce Cockburn
Leonard Cohen
Cowboy Junkies
They Might Be Giants
Barenaked Ladies
The Be Good Tanyas
Moxy Fruvous
The October Project
Miles Davis
Nat Adderly
Buddy Guy
Allman Brothers
Gordon Lightfoot
Dropkick Murphys
Black 47
Bela Fleck & the Flecktones
The Roches
Kate and Anna McGarrigle
Butthole Surfers
Dead Milkmen
Strapping Fieldhands
Black Oak Arkansas
Foghat
Canned Heat
Ravi Shankar
Rory Gallagher
The Eagles
The Amboy Dukes
Ted Nugent
Joan Armatrading
Rosanne Cash
Little Feat
Martin Sexton
Kim Richey
North Mississippi Allstars
Chris Smither
Leon Redbone
The Robert Cray Band
BeauSoleil
Lucy Kaplansky
Mary Chapin Carpenter
The Dry Branch Fire Squad
Nitty Gritty Dirt Band
Lost City Ramblers
John Fahey
Garnet Rogers
Stan Rogers
Richard Shindell
Martin Sexton
Jonatha Brooke