Since you asked, I gotta say Buckethead. He's evolved in the last 8 years and has created a staggering 300+ albums of great material called "Pikes". He has them all on his bandcamp (music.bucketheadpikes.com).

He does more than just notes-per-second faster than anyone. He plays and writes with real emotion as in "Watching Boats with my Dad", "Lone Lagoon", "Cloud", and" Ancient Desert" (and 200+ other songs). Someone put together 12 hours of his soft music linked at bottom.

His collaboration with Les Claypool and the late great Bernie Worrell (Colonel Claypool's Bucket of Bernie Brains) was a legendary live show.

He's great live and well as the studio...And nunchucks! Also a mention for Buckethead's guitar hero, the late great Shawn Lane.

12 Hours of Softer Buckethead:

9 Hours of heavier stuff

Live sample: