Looking for epic songs

Hmm.. there are plenty of heavy-epic songs. So long as the definition of 'epic' does not merely mean 10+ minute songs!

King Crimson
Album : Red Track 1 Red, Track 5 Starless, holy shit is that song heavy, epic and chilling, especially towards the end.
Album: Larks' Tongues In Aspic Track 6 Larks' Tongues in Aspic pt II

Änglagård
Album: Hybris Track 1 Jordrök
Album: Epilog Track 2 Höstsejd

Devin Townsend Band
Album: Terria Track 2 Mountain, Track 3 Earth Day, Track 4 Deep Peace

Sleepytime Gorilla Museum
Album: Of Natural History Track 2 The Donkey Headed Adversary, Track 3 Phthisis
Album: In Glorious Times Track 1 The Companions, Track 2 Helpless Corpses Enactment

Negură Bunget
Album: Om Track 2 Tesarul de lumini, Track 4 Cunoaşterea tăcută
 
Some Songs:
Tool - Third Eye
Porcupine Tree - Russia on Ice
Agalloch - In the Shadow of Our Pale Companion
Black Sabbath - Black Sabbath
Slayer - Reign in Blood
Metallica - ...And Justice For All
Testament - For the Glory Of...
Pink Floyd - Shine On You Crazy Diamond
King Crimson - Starless


Albums that are almost entirely epic:
Tool - Lateralus (you get epic climaxes in The Grudge, Parabola, Ticks and Leeches, Lateralus, Reflection, AND Triad)
Bathory - Hammerheart
 
Between The Buried And Me - Colors (the whole album)

Also give Novembre's album Materia a try. Not as progressive (is it even progressive at all? I can't tell), but the sporadic death vocals give me chills.
 
Rime of the Ancient Mariner - Iron Maiden
The Thing that Never Was - OSI
The Lodge - Agalloch
2112 - Rush
The Sleep of Restless Hours - Disillusion (Whole album actually kicks ass)
Blood Fire Death - Bathory
De l'Echec et de son Essentialite [point 1. Marginalite Demystifiee]
Ils Brandiront leurs Idoles - Mirrorthrone (both songs)
For End Yet Again - Arcturus

Anything from Moonsorrow thats over 8min is epic.
Viides Luku: Havitetty ---> 2 songs one 30min the other 26+. Great album!