Norwegian stuff is pretty good. "Heaviest" depends on your preference. Check out Bathory, Emperor, Burzum, Zyklon and Mayhem.. they're some of the "heavier" things that I can think of off the top of my head.
"Giles" by Unearth"The Dagger" by Roadrunner United"Nemesis" by Arch Enemy"Determined" by Mudvayne"Walk with me in hell" by Lamb of God"Pull Harder on strings of your martyr" by Trivium"Bed of Razors" by Children of Bodom"An Epic Time Wasted" by Avenged Sevenfold"To the fallen hero" by God Forbid"Live For This" by Hatebreed"Wish I had an angel" Nightwish
