Joe Satriani is a favourite guitar player of mine. Top 3 for me (and possibly Jess ;-)
Reason #71 is the name of his new album:
Professor Satchafunkilus and The Musterion Of Rock
For reason #70, check out this video where he explains music theory. Modes are scales. He uses sophisticated terms such as lydian, aoelian, raised 4th, etc, but don't worry about that: just listen to the moods that he evokes. And his style of exposition which is pretty much what I strive for (in general, when explaining computer science, guitar, award-winning blog writing, etc).