George Harrison does an excellent cover of "If Not For You" on All Things Must Pass. I like it better than the original...although on the Bootleg Vol.1 there's a recording of them playing it together...coolness.

I also ADORE former Social Distortion frontman Mike Ness's rockabilly romp through "Don't Think Twice" on his country/rockabilly album Cheating at Solitaire. When Mike sings it, it IS a blow-off song, no bones about it! And he kinda adds a neat little coda to the end which makes it different from all the other covers I have heard.

I also have Irish singer Sinead Lohan doing a GORGEOUS job on "To Ramona". Beautiful. She adds a classical guitar to give it a hint more of the Spanish-y sound.

Come to think of it, U2 does a pretty neat cover of "All Along The Watchtower" themselves.