What you want is a consistent driving amped-up atmosphere. Put it on and play it all the way through album. If it gives you the scrunched up nose like you smelled something bad, even better. So ...
Metal with training wheels (very accessible):
Dee Snider - For The Love Of Metal
Grim Reaper - Rock You To Hell
Primal Fear - Delivering The Black
A little bit heavier:
Testament - The Ritual (A driving album from start to finish ... accessible to most ... mildest of this category)
Fight - A Small Deadly Space (Rob Halford's band)
The next step up (vocals start to become harsh):
Testament - Demonic (A little more brutal)
Born From Pain - Sands of Time (Even more brutal, but with consistent drive. This is the kind of stuff I listen to while weightlifting)
Hatebreed - Perseverance (like Born From Pain, Hatebreed is of the hardcore genre, and hardcore is definitely made for fighting)
Feasting On Darkness - The Black Cloud (instrumental ... if you just want the brutality w/o the extreme vocals)
Feasting On Darkness - Souls of Chaos (instrumental)
D.A.M. - Human Wreckage
Benediction - Killing Music (Appropriate name huh? ... now we're delving into mild "death" metal)
Crowbar - The Serpent Only Lies
Drop the hammer:
This is the point where the vocals might be a problem for the uninitiated and the music may just be too heavy, but if not, these are some really driving brutal albums ...
Dyscarnate - With All Their Might (this album makes me want to lift a house)
The Destro - Harmony Of Discord
Cataract - With Triumph Comes Loss
Stampin' Ground - Carved From Empty Words
Imprisoned - Hard To Kill
Born Low - The Hunger Within (EP ... only 15 minutes)
Deicide - In The Minds Of Evil (a little faster, but still driving)
I also second the Pantera recommendations, especially Vulgar. And also the Pantera clone Throwdown - Venom & Tears
