I usually prefer originals but I can think of a few covers that I actually like better. Absolutely love MollyHatchet's version of The Allman's Dreams. Van Halen obviously did The Kink's You Really Got Me justice as well as Where Have All The Good Times Gone. The Jeff Beck Group does a killer version of Freddie King's Going Down. Gary Moore does a nice metal cover of The Yardbird's Shapes Of Things. Speaking of The Yardbirds, Blackmore's Rainbow took Still I'm Sad and made it their own. Awesome insturmental version on the debut album and with vocals on live recordings. Gov't Mule covers Deep Purple's Maybe I'm A Leo pretty damn good. Those are a few I can think of for now. Whatcha'll think?