[Barone1551]

First i will say i gotta go with keaton on this one Mastodon has gotta be up there. Although i prefer Leviathan, Blood and thunder is awesome.

Then the rest:
Protest the hero
Abigail Williams
All that remains
Amon Marth
Buckethead-Cuckoo Clocks Of Hell
Devildriver- Clouds over California
Dethklok
Pelican
Job for A Cowboy
Yakuza

Not really metal but they get a special shout out, and they are still pretty hard:
The fall of Troy
Enter Shikari
Irepress