It Makes No Difference - The Band
This is one of those songs that could easily be 23 minutes long and you wouldn't even notice.
Also noteworthy: My Morning Jacket's cover
Dylan's "Ballad of a Thin Man"
The Black Crowes' "Sometimes Salvation."
Klazz Brothers and Cuba Percussion/JS Bach's "Air"
Grapes of Wrath's "You May Be Right"