Nick Drake's guitar work was super tech, it hurts to listen to it sometimes, just knowing what went into playing what you're hearing. Steve Howe from 'Yes' the guy is a genious, if you ever get ahold of some of his music and just glance over it, it blows your mind, that is if you can read music. His usage of 40+ different chords in many of his songs, confusing ass progressions on top of some crazy finger picking... They're both mainly acoustic, definately on top of the list though.
'...Smoking's bad, smoking killed my dad. Yeah, he was driving down the highway one day and as he was lighting his cigarette, it blew out the window. So he jumps out the door to save it, and ran himself over. Uh, you mind if I smoke?' -Olie Ollaussen, Ski Bum extraordinaire