Simon and Garfunkel
The Gothard Sisters
I feel like i may be one of the few who actually likes Aliens Ant Farm's Smooth Criminal...
But then again, I suppose I enjoy the catchyness of pop with the hard edge of rock.
For example Silverstein's rendition of Apologize is far more appealing to me than One Republic's.
Wow- lots of great covers listed here-
The Type O Negative and Devo covers in particular are great.
A few not up here yet:
Black Hole Sun- Cibo Matto-(Soundgarden)
You Only Live Twice- Nature-(Nancy Sinatra)
Kashmir (and most other LZ covers)- Dread Zeppelin-(Led Zeppelin)