Too many to mention! Here's a most and in no particular order
Eddie Van Halen Randy Rhoads George Lynch Jake E Lee Steve Vai Zakk Wylde Chuck Schuldiner Criss Oliva J (White Zombie) Bruce Bouillet Mick Marrs Nuno Bettencourt Richie Kotzen Tracy G Al Di Meola Paco De Lucia Munky & Head Jeff Waters Gary Holt Robb Flynn & Phil Demmel Rocky George John Sykes Dimebag Darrell Harry Cody (Shotgun Messiah) Billy Duffy Billy Gibbons Joe Perry The Holy Trinity of course Jimmy Page/Jimmy Hendrix/Jeff Beck Warren DiMartini CC Deville
The usuals: Petrucci, Vai, Satriani, Gilbert Also Jerry Cantrell, Mark Tremonti, Guthrie Govan, John 5, Jeff Loomis, Randy Rhoads, James Hetfield, Dimebag, Stephen Carpenter, Emil Werstler, Tosin Abasi, Adam Dutkiewicz, Clint and John from Sevendust, and Joe Bonamassa
Those who pop into my mind instantly... obviously there are more, but I just don't feel like making a huge list at the moment I also didn't write Devy because I admire him for singing and compositional skills more, rather then his guitar skills (not to say he doesn't have skill of course)
In addition to many mentioned in this thread and many not mentioned, some of my favorites that I feel need mentioning are Ritchie Blackmore, Marco Sfogli, Per Nilsson, Jani Liimatainen, and Michael Romeo.
I'm going to avoid putting out a whole list since a lot of it would be copy/paste from others and it would take forever to get them all in.
Marty Friedman Paul Gilbert Jason Becker Steve Vai Guthrie Govan Tom Morello Jason Richardson and Lee McKinney Tom Hollings and James Clayton Devin Townsend Pilini (Halcyon, prh) Dan Weller Django Reinhardt Paul Masvidal