What metal songs have blown your mind?

I have nothing to do atm. So what the hell, I'll try to get a pretty complete (long) list.

Aeternus - Sentinels of Darkness
Agalloch - Hallways of Enchanted Ebony
At the Gates - TRITSIO (start to finish), Gardens of Grief, first half of WFIKTBD
Amorphis - Black Embrace
Bathory - A Fine Day to Die
Black Sabbath - Into the Void and Symptom of the Universe (both were years ahead of their time)
Candlemass - Black Stone Wielder
Coroner - Reborn through Hell
Danzig - hard to choose, so I'll just say 777
Death - Pull the Plug (most brutal song of all time)
Death Angel - The Ultra Violence
Deathspell Omega - First Prayer
Decapitated - Spheres of Madness
Demigod - Perpetual Ascent
Destroyer 666 - Genesis to Genocide
Dissection - Black Horizons
Exhorder - Anal Lust
Fleshcrawl - Lost in a Grave
God Macabre - Into Nowhere
Grotesque - Blood Runs from the Altar
Hammers of Misfortune - The Locust Years
Heathen - Death by Hanging

.... actually I'm kinda bored now. That will do .... although it's not actually that long.
 
Dark Tranquility - Of Chaos And Eternal Night
Soilwork - Nerve
Hammerfall - Hearts On Fire
Elvenking - White Willow
Skyclad - The Silver Cloud's Dark Lining
 
Dark Tranquility - Lost to Apathy
Dark Tranquility - Focus Shift
Dark Tranquility - The Gallery
Iron Maiden - Hallowed be thy Name
Iron Maiden - Seventh Son of a Seventh Son
Iron Maiden - Paschendale
Iron Maiden - Dance of Death
Bathory - Blood Fire Death
Agalloch - Not Unlike the Waves
At the Gates - Suicide Nation
Death - Pull the Plug
Gojira - Global Warming

There are many others.
 
Meshuggah - Future Breed Machine
Meshuggah - Bleed
Opeth - Godhead's Lament
Death - Mentally Blind
In Flames - The Jester's Dance
Dark Tranquillity - Cathode Ray Sunshine
Iced Earth - Dante's Inferno
Symphony X - The Odyssey
Agalloch - Not Unlike the Waves
 
Dark Funeral's Diabolis Interium(whole album)
Judas Iscariot's Heaven in Flames(whole album)

I can't get enough of both of these albums.
 
Agalloch "In The Shadow Of Our Pale Companion"
Every time I hear this song it blows me away and I never get sick of it.
The mood that is created in this song cannot be duplicated.

That's one of the few Agalloch songs that actually has some good melodies to it, I think. Most of their riffage is just really weak in comparison.

Yeah, bring on the flames from the rabid Agalloch fanatics.
 
Artillery - Khomaniac - I must have hit repeat at least 10 times when I first heard this melodic gem.

Therion - The way - Now that's how you make an epic, dm song. take notes, opeth

Cauldron Born - Blood bath in the arena - High pitched vocal melodies that would make even James Rivera tip his hat too, plus a sick solo.

ADX - King of Pain - rifftastic. A shame that most metal fans don't know about ADX


D666 - Genesis to Genocide - Yes, it's even better than the ST

Anacrusis - ROT
 
The Cathedral cover of Pentagram - All Your Sins is pretty much mind blowing.

There are plenty of original songs that blow my mind, but a few covers have been sufficiently excellent to also make me truly think "wow".

Solitude Aeturnus - No More Tears is an example of taking an (extremely) average track and transforming it into something very special.