Old blues song - probably best known as a Muddy Waters song.  http://www.youtube.com/watch?v=c2GiCKKO390 

Also recorded by Elmore James, Cream, Canned Heat, Johnny Winter, Jeff Beck and RL Burnside - to name a few.  
My favorites are RL Burnside - it has plenty of soul
http://www.youtube.com/watch?v=Q7PdxdXzskU


and Jeff Beck/Imogene Heap - it has plenty of Jeff Beck.  
http://www.youtube.com/watch?v=uuXcGHjBeac

You? 

I like em all.

:-)

But this one seems extra rootsy:

http://www.youtube.com/watch?v=LO9q-MObuDU

I kinda like the Jeff Beck/Imogene Heap because she has all her teeth and I could consider making out with her again.