My top 20 in no specific order:
Angus Young
Jimi Hendrix
Tony Iommi
Frank Zappa
Rev. Blind Gary Davis
Keith Richards
Chuck Berry
B.B. King
Uli Jon Roth
Ritchie Blackmore
Ted Nugent
Randy Rhoads
Buddy Guy
Malcolm Young
Yngwie Malmsteen
Johnny Ramone
Hubert Sumlin
Lead Belly
Pete Townshend
John Lee Hooker
Do people even listen to Slayer for the solos? I only really pay attention to the riffs and the drums. I can't remember how any of their solos go.
Robert Fripp (King Crimson), Alex Lifeson (Rush), Jimi Hendrix
He was also the first to come to my mind for the same reasons.Tommy Vetterli is my number one. Flawless technique, super tasteful solos, flash without wank, and he's written some of my favourite riffs.
My second pick is Piggy aka Denis D'Amour whose guitar-playing is IMO mainly responsible for the unique Voivod-sound.