Cover that stains the original and almost makes me not want to listen to it again:
Smooth Criminal, Alien Ant Farm
I have heard a Dave Matthews Band Cover of All Along The Watchtower.
This has to be the coldest, biggest fist to the cock ever.
WTF!!
And to be constructive, that self titled Bob Dylan album is chock full of them. Not going to lie, I'm not familiar with a lot of the originals, but the one's I am are winners...
You're no good- Bob Dylan - Jesse Fuller
House of the Rising Sun- this is one I'm not certain who originally wrote it, and where I've heard it before, but I assosciate it with Bob Dylan because of this version. I give it tie status on grounds that I can't pinpoint original.
I love the Devo cover too.
And the Low+Dirty Three cover (off the fishtank album) of 'Down by the River'- Neil Young I like a lot as well. This is a tie though.