It's hard to do a list. 
Anyway my favorites:
1) Jimi Hendrix
2) Duane Allman
3) Mike Bloomfield
4) Terry Kath
5) Ritchie Blackmore
Honorable mentions go to many guitarists.
Some of them are:
Carlos Santana, Ollie Halsall, Frank Marino, Jeff Beck, Jimmy Page, Steve Ray Vaughan, Robert Fripp, Robin Trower, Richard Thompson, Fred Frith, Steve Howe, Rory Gallagher, Warren Haynes, Derek Trucks, Trey Anastasio.
Anyway my favorites:
1) Jimi Hendrix
2) Duane Allman
3) Mike Bloomfield
4) Terry Kath
5) Ritchie Blackmore
Honorable mentions go to many guitarists.
Some of them are:
Carlos Santana, Ollie Halsall, Frank Marino, Jeff Beck, Jimmy Page, Steve Ray Vaughan, Robert Fripp, Robin Trower, Richard Thompson, Fred Frith, Steve Howe, Rory Gallagher, Warren Haynes, Derek Trucks, Trey Anastasio.
