Carpathian Forests' "It's darker than you think" from Defending the Throne of Evil. This song is almost TOO good, as it dwarfs every other song on the album, IMO.
Death - Leprosy
Nightwish - Elvenpath
Metallica - Fight Fire With Fire
Psychotic Waltz - Ashes
Watchtower - Instruments Of Random Murder
The Third And The Mortal - Grevinnens bønn
The Third And The Mortal - Magma
Sieges Even - Tangerine Windows Of Solace
Anacrusis - Present Tense
Anacrusis - Stop Me
Death Angel - Thrashers
Hades - The Leaders?
Mekong Delta - Dances Of Death
Znowhite - To The Last Breath
Flotsam & Jetsam - No Place For Disgrace
Voivod - Killing Technology
Pantera - Strength Beyond Strength
Down - Temptations Wings
Exhumed - Waxwork (disregarding the intro)
Decapitated - Winds of Creation
In Flames - Jotun
Obituary - Infected
Lamb of God - Ruin
Morbid Angel - Immortal Rites, cleansed in pestilence (one of the only good tracks on heretic)
ok some of these are just decent openers, but its hard thinking of stuff that hasnt already been listed