I am sure most of you wouldn't agree with me, but I was rather impressed with the cover of "Saturday Night's Alright" by Nickelback and Kid Rock. It was really awesome to hear it done with some heavier drums and bass.
I swear theirs a thread like this already but mkay.
Eric Clapton- Little Wing (Jimi Hendrix)
Johnny Cash- I wont back down (Tom Waits)
Phil Collins- My Girl (The Temptations)