Dammit, this is a very hard one hey, and I am sure I will log on a thousand times to edit my selection...lets see:

Randy Rhoads
David Gilmour
Mark Knopfler
Omar Rodriguez(how the hell do you spell that, dont you just love ATDI and Mars Volta?)
And my last one...maybe Steve Howe? or Steve Vai? Mikael Akerfeldt? Alexi Laiho?
I cant limit it to just one, but tis Probably Alexi Laiho