Pretty sure this guy is still on the board. Probably should be put under songwriter but as I have that category already filled I'll put him as my
Wildcard Vocalist. Huddie William Ledbetter or Leadbelly. Jack White and Kurt Cobain have taken cues from this man.
http://en.wikipedia.org/wiki/Leadbelly
Check out Son House too who has been covered most notably by the White Stripes. Quite eerie listening to this now and its great.