1) Yngwie Malmsteen (hell.. I even named my dog Yngwie.. no ******* joke) - There is nobody close.. lyrics to songs sucked, and his band was hodgepodge at best.. but he is the epitome of guitar god
2) Angus Young - Yes... power chords.. but much more talented than the average listener would know
3) Steve Vai - Took the teachings of Satriani 1 step further
4) Mark Knopfler - Another under appreciated master of the strings... can be mellow, can actually shred (though Dire Straits music generally does not call for that), and has some damn complex work
Honorable mentions
James Taylor - Yes, a folk player but talk about complexity of melody that is not commonly seen.. but not 'really' rock, so can't make the list
Ritchie Blackmore - The body of work speaks for itself
Randy Rhoads - Oh... what if comes into play here.. what could have been
David Gilmour - Possibly the best studio guitarist EVER
Over-rateds
Jimi Hendrix - 'Controversial' in his time, but senseless crap most of the time influenced by the extreme drug use
Jimmy Page - One of the main reasons why I am a rock/metal fan and I hate Led Zep
Kirk Hammett - Far inferior to even Mustaine
Slash - Another not as good as the guy he replaced.. hype of the band added to the hype of the guitarist