I think epica is pretty fucking epic. Hence the name I suppose. Female-fronted metal, so if you dont like that then dont bother. But if you do, its good shit. Their new album is awesome (youtube burn to a cinder and unleashed ^^). Other related stuff: after forever, stream of passion.. there are others but those are my favorite 3.
If you dig opera, anything by puccini kicks ass and is quite epic. Turandot is like, one of my favorite songs? works? pieces?....regardless. << nessun dorma from Turandot. Probably the most epic male aria ever written.
As far as vocal-less epic music classical is always good. Rodrigos guitar concertos are SO epic (concierto de aranjuez is amazing, especially act 2). Lets see...
The Wreck of the Edmund Fitzgerald! In all seriousness, though, you might want to check out Rimsky-Korsakov's Scheherazade, Op. 35. The first and fourth movement are particularly epic.