Ace Frehley for me, he's the reason I started playing many many moons ago!
An endless list...Impossible to find a guitarist in the previous 3 pages NOT worthy... and impossible for me to pick a favourite,
I tend to play the ones I've seen live a lot more often... From John Mayall's Bluesbreakers in '71, Page in '72 on the Zep 4 tour, through most of the others mentioned in these posts..bar Hendrix of course... to the newer names.
Gotta say tho, Aussie talents right up there.. Angus, Dave Hole, the Emmanuel brothers, Diesel (one of the best duelling guitar sets ever with Alvin Lee on a early 90's aussie tour) and the godfather of Oz rock guitar...Billy Thorpe's guitar teacher Lobby Loyde.
http://www.smh.com.au/news/obituaries/the-godfather-of-australias-heavy-rock/2007/04/23/1177180571669.html?page=fullpage