This list is in relatively close chronological order:
Kiss-1979
Foreigner/Billy Squire
Ozzy Osbourne(w/Randy Rhoads once) 3times
Talas featuring Billy Sheehan
Van Halen(twice with Roth) 5 times
Genesis
Rush
Iron Maiden/Fast Way/Coney Hatch(Hatch rocked!)
Def Leppard/Krokus/Gary Moore
Triumph(Foghat opened once!) twice
Yes
Yngwie Malmsteen 3 times
AC/DC
Deep Purple-twice
Rainbow/Aldo Nova
Stevie Nicks/Joe Walsh
The Firm (Jimmy Page & Paul Rodgers) twice
The Ramones-twice
Metallica-(once with Cliff) 4 times
David Lee Roth
Bon Jovi/Ratt
Eddie Murphy!!
U2 (JT, AB, PM, Elevation) 8 times
Joe Satriani
Steve Vai-twice
Frank Zappa-backstage pass
Eric Clapton-twice
Monsters of Rock-1988-Kingdom Come, Metallica, Dokken, Scorpions, Van Halen
INXS
Robert Plant-twice
Stevie Ray Vaughan/ Jeff Beck
Tom Petty and the Heartbreakers
Alice in Chains
Allman Brothers
John Mellencamp
Coverdale/Page
The Rolling Stones
Violent Femmes
Bullet Boys
Cry of Love
Page/Plant-twice
Soundgarden
Queensryche
Neil Young/The Pretenders
Billy Idol/Slash's Snakepit
Dokken-twice
Whitesnake-twice
Scorpions-3 times
Ronnie James Dio-3 times (once last week!!)
The Who
Paul McCartney
Sammy Hagar/Roth
Joey from NKOTB-A friend of mine is his guitarist
Bruce Springsteen
Slaughter/Kip Winger(he was good, him and an acoustic guitar), Warrant, Whitesnake
Cheap Trick
Aerosmith/Johny Lang
Prince
Living Colour/ Vince Neil
Eric Clapton Crossroads Guitar Festival 2004- Styx, George Lynch, Andy Timmons, Steve Vai, Larry Carlton, Pat Metheney, Robert Cray, James Taylor, Joe Walsh, BB King, Buddy Guy, Jimmie Vaughan, Bo Diddley, Vince Gill, John Mayer, Eric Clapton, Jeff Beck, Carlos Santana, ZZ Top
U2 openers- I can't remember who opened for the JT tour, Primus, ROTM, PJ, No Doubt
I'm sure there are more, but I can't remember since I'm old.