Bloomfield was great and if he had lived beyond 1971 I'm sure would have been near the top of the list. Most folks think you have to be black to really play the Blues but there were a lot of white blues guitarists who IMHO could really rock the house dowm. Quite a few have already been mentioned - Clapton, Hendrix, Page, etc and a few who haven't. I particulary like the British Blues Bands from the 60's. I had the good fortune of living in Europe from age 17 - 20 and saw many great bands at clubs in Frankfort, Munich, Heidelberg, Amsterdamn and London (I was an AirForce Brat) as well as going to LeMans 3 times and hitchiking to most of the Gran Prix cicuits in the summer and ski bumming during the winter. One of my favorite bands back then was Chicken Shack - doubt many know what band it spawned and who the lead singer was. Unffortunately my great lifestyle ended in 66 when I was selected to serve by the Selective Service Administration.
YouTube - Christine Perfect with her Chicken Shack -Mean Old World