In reply to The Lemming: For lead guitar, then for me it is the guys who owned the stage, and the rest of the band were just there to support them and their axe weilding wank fest.
So guys like Eddie Van Halen.
ozzy osbourne has always valued his guitarists, Randy Rhoads, mentioned a few times already. Jake E lee was great IMO, also Zakk Wylde. All proper LEAD guitarists, showmen that half the audience turned up just to see them.
I personally find the Joe Satriani's and Steve Vai's of this world a bit soulless, possibly because they can't actually write a decent tune around their flashy solos.
Angus Young and Jimmy Page are good shouts above. In fact, lot's of good shouts. Matthius Jabs, Walter Becker, Slash,
but my two favourites would probably be John Sykes and Eddie Van Halen