Duffy, here's my votes:
The Devin Townsend Project > Dir En Grey
Sepultura > Between The Buried And Me
(As much as I like BTBAM, Sepultura from 1984-1996 is fucking classic shit. Plus, Sepultura still kicks ass live)
Megadeth > Skeletonwitch
Judas Priest > Dying Fetus
Animals As Leaders > Bolt Thrower (Weird comparisons, but i've never been too into Bolt Thrower)
Cannibal Corpse > Dimmu Borger
Bloodbath > In Flames
Decrepit Birth > Trivium
Suffocation > Born of Osiris
Obscura > Exodus
(FUCK newschool Exodus, seriously)
Motorhead > Lamb of God
(I don't even like Motorhead and i'm voting them, damn)
Dark Tranquility > Meshuggah
Job For A Cowboy > Whitechapel
(LOL)
Opeth > Wolves In The Throneroom
(This one was very hard for me to do, but I had to. Plus, WITTR doesn't stand a chance in the first place)
Deicide > All Shall Perish
Obituary > Behemoth
(The fact that Behemoth is winning is depressing)
Goatwhore > Avenged Sevenfold
Rammstein > Children of Bodom
(I hate both, really)
Ensiferum > The Faceless
Nile > Arch Enemy
Cynic > Napalm Death
The Black Dahlia Murder > As I Lay Dying
Testament > Immortal
Swashbuckle > Amon Amarth
Aborted > Veil of Maya
Kreator > Slipknot
Mastodon > Warbringer
(Either way, whomever wins is going to crushed by Maiden in the next round)
Iron Maiden > Machine Head
Morbid Angel > Gojira
Enslaved > Decapitated
Anthrax > Metallica
King Diamond > Slayer
These are all my votes. Also, replace the core bands with say... Rhapsody of Fire, Blind Guardian, Nightwish, Stratovarius, Gamma Ray, Kamelot, Symphony X, Manowar, Iced Earth and Epica. Seriously.