To catch Harrison and Lennon in top form, check out "I Want You (She's So Heavy)" off the "Abbey Road" album. Lennon does the lead, and Harrison is doing the arpeggios. Both of 'em get in some pretty creditable and original blues licks in that tune.
Zakk Wylde
Eddie Van Halen
Randy Rhoads
Slash
BB King
Gary Rossington (Skynyrd)
Dimebag Darrell
George Lynch
Prince (yeah you heard me)
Gordon Lightfoot
Good call on Gary Rossington. You could also throw Allen Collins in the mix, and I believe Ronnie Van Zandt was the greatest frontman ever. Lynyrd Skynyrd only recorded for 4 years and they were really just getting started when their plane crashed. What a waste, a lot more great songs that we'll never here.