What about Seether covering careless whisper! I love that one!

Killswitch Engage's cover of Dio's Holy Diver is the best cover I've heard so far.
Adding the Killswitch Engage sound without changing the song itself.
Flawless.
So Flawless that I can listen to Killswitch Engage's version and Dio's original version and like them both equally.

I couldn't really comment on Killswitch Engage's version, I have seen it on scuzz and Kerrang a few times. Being of a certain age I used to have most of Dio's albums on vynyl including Holy Diver. A brilliant voice, Mystery and Hungry for heaven are my favourites, he was the best singer in Rainbow I would arue as well.

Not heard that one but I do rate Limp Bizkit's cover of Faith

Leningrad Cowboy's cover of Yellow Submarine
http://www.youtube.com/watch?v=q2oQAXyYzpA

Have to say I also liked Type O Negative's covers of Hush-Deep Purple and Cinnamon Girl, but I can't remember who originally did that.

Then as I made that post while listening to my mp3 player. Faith No More's cover of Black Sabbath's War Pigs came on.

Haven't heard the War Pigs cover but FNM's cover of Easy by the Commodores is ok. The original Cinnamon girl according to Wiki was by Neil Young off the everybody knows this is nowhere album. Strange thing is and I kid you not one of my favourite lecturers at uni who I am still in touch with is called Cinnamon. I called her the sixth Spice Girl but not to her face I might add!!

I really like Disturbed's cover of Genesis' Land of Confusion. They also did a bang up job on Tears for Fear's Shout.

Yes I like disturbed's Land of Confusion, the video is very clever too. I have a couple of their CD's, not heard Shout though although I know the origianl very well.

all along the watchtower by savage grace (1970)

http://www.youtube.com/watch?v=UjPHJAsG48Y

listen for yourself

linda ronstadt - your no good

Heart - without you

three dog night - one

soft cell - tainted love

Smooth Criminal is a good choice.
My personal favorite is Otep's Not to Touch the Earth. I love the original too, but I thought Otep added more intensity and atmosphere to the piece. The intro has made me jump more than once.

roseanne cash

tennessee flat top box (it was her daddy's)

Disturbed's version of Shout is tres awesome!

Yep Soft Cell's tainted love was a good cover, as was Marolyn Manson's of the same song

Cardigans version of iron man...

Leona Lewis - the first time
that lady can sing

Megadeth cover version of never say die and paranoid by black sabbath..

311 cover version of love song by the cure