Wow, thanks for re-introducing me to Rev. Blind Gary Davis. The stuff I have isn't too great I think, but this is awesome stuff!
Magic Sam is pretty badass too!
I love that Beefheart song. This one must be my favourite video of the Captain. I love the way they rock out:
Brother ghost, who is Sylvester Weaver? Never heard of him.
Blind Boy Fuller and Son House, those two nail it for me. Every one in his own distinct style. Pure awesomeness.
Also Skip James and Blind Willie McTell and Robert Johnson. I could listen to these guys all the time.
I got a collection called the Alan Lomax Blues Songbook. On it is the best version of Rolling and Tumbling ever, by Rosalie Hill. If you get a chance to - listen to that. Amazing version. (Dylan's on Modern Times is pretty amazing too.)
Also there are old demo recordings of Nick Drake, where he plays amazing blues guitar.