Hallelujah - Leonard Cohen - Jeff Buckley, his performance of this song is easily the best cover ever.
No Quarter - Led Zepplin - Tool, if anyone should have done this song, it was Tool.
You Really Got Me - The Kinks - Van Halen, Eddie playing the opening riff...come on...
Sweet Dreams - The Eurythmics - Marilyn Manson, take a disturbing sounding song, give it to a disturbing band...awkward gold.
Pokerface - Lady Gaga - Eric Cartman, Kyle Broflovski, and Kenny McCormick...of course.
Johnny Cash - Folsom Prison Blues - Brandi Carlile, she's truly awesome.
Creep - Radiohead - Brandi Carlile, like I said, she's truly awesome.
The Thing That Should Not Be - Metallica - Primus, because THAT'S WHAT YOU GET WHEN YOU DENY LES CLAYPOOL!!! YEAH! STUPID LARS! SHUT UP! NAPSTER BITCHES!!!
Intruder - Peter Gabriel - Primus, weird knows weird...
Amos Moses - Jerry Reed - Primus, what can't they do?
Holiday in Cambodia - Dead Kennedys - Foo Fighters feat. Serj Tankian - Must sound like Jello Biafra when singing this song, otherwise it sounds wrong. Serj did that. Good job.
Dancing Days - Led Zepplin - Stone Temple Pilots, best song on the album, which on the whole, was lousy.
Most everything off of Nativity in Black - Black Sabbath Tribute Albums (1 + 2 (except for the remarkably lame Busta Rhymes "Iron Man" cover))
and...
Everything Richard Cheese has ever done...period.
I know I'm missing a lot of good ones, but if you put these songs onto a mix tape...she'll fuck...trust me.