Part Two of Mahler's 8th Symphony.

But if we're talking rock-era, I would probably pick the whole of Yes' Tales From Topographic Oceans album, which is properly understood as one epic rock work of four movements.

Pink Floyd's Dogs.

Duh.

While I am not surprised Yes was the choice de jure....I am surprised you didn't drop Close to the Edge, or And You and I.

Roses by Outkast

i made it to 32 seconds before refusing to watch anymore of that video

if only i still had that much hair, but then again, I don't think I ever had that much hair

I always laugh when I see that scene of Stallone beating Carl Weathers. It's obiouvs that Weathers isn't even going past first gear let alone really running, and Stallone looks like his head is going to explode.

The Cronenberg remake would be cool.

Well, I was very tempted to go with CTTE. Perhaps it would be the best choice since it actually adheres to the form of a song (being essentially an extremely elongated AABA format--verse, verse, bridge--the "I get up, I get down" section--and final verse).

But while I still have the floor here, I really want to say something about most of the choices being flouted in this thread so far. I try not to sound arrogant on these forums, but these are really some of the lamest ideas of what an "epic song" would be that I've ever seen offered. "More Than A Feeling"??? I mean, why would one name that Boston track as opposed to "Foreplay/Long Time" (which at least has some complexity and development about it--not that any Boston track truly qualifies as an "epic song")?

The first thing that one should look at when qualifying an "epic song" should in fact be the length. That's the essential qualifying factor of anything that would be referred to as "epic". Beyond that, the dramatic scope and lyrical narrative of the song should be considered. Those two factors alone would disqualify a song such as "More Than A Feeling", which is under five minutes even in its unedited "album version" form and lyrically addresses nothing more dramatic than missing one's ex while listening to the radio (I mean, come on already!)...

And by the way, I actually am a fan of Boston and have always liked "More Than A Feeling" as a really great guitar rock ballad...but epic??? I don't think so...

At least "Bohemian Rhapsody" and "Stairway to Heaven" have the dramatic factor working in their favor, although neither of them are truly "epic" in length--I mean, "Bohemian Rhapsody" was actually a 45 RPM single...unedited!

While I can understand how rock fans could choose either of those as a candidate for "most epic song", I would still insist that any song which could fit on a 45 RPM single doesn't qualify...and by the way, "Stairway to Heaven" is only a few seconds longer than "MacArthur Park", the longest 45 RPM single ever.

As for "Paradise By The Dashboard Light"...you're joking, right?

At least no one has yet nominated "November Rain" by Guns and Roses...that would be the true collapse into canyons of absurdity.