Here's another vote for Blind Willie McTell's "Statesboro Blues." It's certainly one of the most verstile blues songs ever written, I've never heard it played the same way twice.

It's got me thinking of other songs that have gone from the country into the mainstream. "If I Had Possession Over Judgement Day" predates Robert Johnson but his version is the most memmorable. That became Muddy Waters' "Rollin and Tumblin" which was later recorded by white rockers. "Walkin Blues" also came to the mainstream via RJ and Muddy Waters. "Dust My Broom"; RJ and Elmore James.