I was just going to say what Brian said. Everytime I see a thread like this, I think of a different answer.

SOME of my favorites are:

Son House - Death Letter Blues and Empire State Express

Mississippi John Hurt - Let the Mermaids Flirt with Me and Louis Collins

Mance Lipscome - Charlie James and Silver City

Charley Patton - Some Summer Day and Elder Green Blues (which seems to have a tune similar to Charlie James)

Murray