Impossible to narrow it to 10, so here's the ten I'm listening to at the moment: (mix of metal core, metal, and all sorts actually)

As i lay dying
Devildriver
Architects
Otep
Bolt-thrower
Monsterworks
Trivium
In flames
Slipknot
Cryptopsy when I'm in the mood

Iron Maiden
Judas Priest
Metal Church
Megadeth
Metallica
Black Sabbath
Slayer
Mercyful Fate
Manowar
Pantera

I'm probably gonna be the only person on this thread that says this, but generally I prefer "core" bands. Hate me. Anyway, to stick to typical metal guidelines....

1.In Flames
2. All That Remains
3. Nekrogoblikon
4. 3 Inches of Blood
5. Toxic Holocaust
6. Behemoth
7. Alterbeast
8. Thy Art is Murder
9. Sworn Enemy
10. Darkest Hour