if I had to pick one person as the best (well known) guitarist of all time I would have to go with Clatpton. not only can he play amazing while he's sober, but he was able to play some of the best songs ever while completely strung out on heroine.
I idolize him so much I've often thought about taking up heroine, getting addicted, and then quitting so that if I ever meet him we'll have something to talk about.