There are so many guitarists out there with other-worldly skill that play music that I would guess that most of the folks on here never listen to. These guys play classical, flamenco and other styles. Watching them play, as a guitarist (and drummer) myself, makes me want to sell all my music gear and buy a Kazoo.
Anyway, for the rock/blues genre, I submit one of the best is James Burton. Not many will know who he is, but every one of you has heard his music! He played with Elvis for many years. Never cared much for Elvis until I heard the live stuff in which Burton shreds on his Telecaster. Fender guitars knows who he is, which is why they produced a commemorative James Burton Telecaster.