Dustbury notes a web poll crediting noted Seattleite Jimi Hendrix as having the best guitar riff ever.
I'd like to throw in a vote for Joe Satriani, who admits to being a Hendrix disciple. Here, in probably my favorite track by Joe, he takes the brutally simple figure "da-duh da-duh", and sets it on fire. The whole thing is incinerated by 2:00 into the track.
Then, just to show you what a genius he is, Joe brings it back and works it at a medium pace. The second half of this track seems (to the non-guitarist) to pick up right where Hendrix's reading of "All Along the Watchtower" left off.
"Chords of Life" is off of "Strange Beautiful Music", which is a desert island release, as far as I am concerned.
Update: from the comments, Trio Rypdal does indeed set standards:
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