I'll start with a couple favorites of mine and provide a few comments (not necessary, but fun)

Aztec Camera – Jump
A very mellow cover of Van Halen's Jump.

Johnny Cash – Hurt
This is a fabulous song (even when it sounds like he says "my Swedish friend" rather than "my sweetest friend"), but many people haven't heard the darker original from Trent Reznor Nine Inch Nails (NIN) - Hurt.

Jeff Beck – People Get Ready (With Rod Stewart)
Very similar to the original from The Impressions, but Jeff Beck and his guitar add that extra layer to push the cover beyond the original.

Marilyn Manson – Personal Jesus
Now I'm not huge fan of this song, but Marilyn adds what Depeche Mode missed.

Korn – Word Up!
I have to include this, but the original by Cameo is still better. I like them both and this is my post. We can argue later!

The Wallflowers - (What's So Funny 'Bout) Peace, Love, and Understanding
Since I've begun plucking a guitar, I can appreciate a good acoustic version of a song (Hey, that's a good idea for another playlist/group). Anyway, the original by Brinsley Schwarz as well as the better-known version by Elvis Costello & The Attractions still rock more.

Milow – Ayo Technology
Now this is a contrast. Even though it's been way too overplayed on the radion, it's still a solid cover that should make 50 Cent proud.

Limp Bizkit – Behind Blue Eyes
Don't misunderstand me here because The Who totally get my nod as the better song, but Fred Durst and the fellas did a pretty good job bring this fantastic song to a new generation.

Chris Cornell – Billie Jean
A solid, intense version of the Michael Jackson classic by the former Soundgarden frontman.

Faith No More – Easy
Sounds very similar, but without having to deal with Lionel Ritchie's pipes on the original version by the Commodores.

John Mayer – Free Fallin'
Another one where I have to say the original from Tom Petty and the Heartbreakers is still better, but this accoustic cover is pretty sweet.

Sarah Masen – Give A Little Bit
I always thought Supertramp should have had a female vocalist sing this song. I was right.

Alien Ant Farm – Smooth Criminal
A heavier version of the MJ classic.

Gipsy Kings – Hotel California (Spanish Mix)
For a fun way to practice you're Spanish. The Eagles still own it!

Placebo – Running Up That Hill
Kate Bush is still my girl, though.