Cradle Of Filth - Hallowed Be Thy Name (originally by Iron Maiden)
I'm gonna get slagged because a lot of metalheads despise CoF. =\ Nonetheless, I love the new twist CoF brought to the song. I miss the dual guitar harmonies and stuff, but the sheer feel of the song and all the creativity that was put into making this song their own...whether you love CoF or hate them, you gotta give 'em props for making a great song their own.
Opeth - Remember Tomorrow (originally by Iron Maiden)
I actually like Mikael's voice in this song over Bruce Dickinson's...it really fits this song in a way that Dickinson, much as I love his style, doesn't quite match. It feels a little slowed down and more mellow, but it retains a sort of flavor that's distinctly Opeth and Iron Maiden at the same time. Another great Iron Maiden cover, which shows the strength of Maiden's songwriting and the instrumental firepower of Opeth. Recommended.
Pantera - Electric Funeral (originally by Black Sabbath)
What can I say? It's one of my all-time favorite Sabbath songs. Pantera just made it a hell of a lot more crushing. In fact, I'm tempted to say their version is a lot better (though production value's got to be considered, the quality's a lot better than what Sabbath could've done in the 70's)
Racer X - Children Of The Grave (originally by Black Sabbath)
I actually heard this version before I heard the original. I loved the song right off the start, but I actually prefer Sabbath's version. Nonetheless, Gilbert and co. manage to pull it off superbly, with some nice shred aesthetics pulled into the mix (think those crazy Randy Rhoads style fills
AFI - Last Caress (originally by the Misfits)
Davey's voice doesn't really do Glenn Danzig's performance justice in my opinion, but they pulled the song off well. It's pretty much the same thing, except the production's a lot crisper and the feedback extends the song by a few seconds. It's easy, but it's pretty much perfected.
Shadows Fall - Welcome To The Machine (originally by Pink Floyd)
It's a nice metal cover of a psychedelic rock song. It's not as weird as the original, nor as claustrophobic and spacey. It doesn't drag in that typical prog way either (well, it is a metal version), and to top it off, Brian Fair and Matt Bachand do a pretty good Gilmour/Waters impersonation.