Man, I haven't listened to my copy of Muddy's "Hard Again" in years - I'm going to put it on the 'table tonight.
A recent CD you all might want to check out is something called "Exile on Blues Street". It's songs taken from the Rolling Stones "Exile on Main Street" album, but done by assorted blues artists. Very interesting versions, and great sound as well. I think there is also a similar CD from the same series that is songs from Bob Dylan's "Blonde on Blonde" (Called something like Blues on Blonde, or Blonde on Blues, etc.) Bob Dylan might not be as obvious a source of blues songs as the Stones ("Leopard-Skin Pillbox Hat" notwithstanding), but it's all a matter of interpretation!