So I guess I'll fufill the sacred Internets requirement of linking to this whenever Holst is mentioned.

Rachmonanov's Piano Concerto #3 (aka The Rach 3) is an awesome classical piece...I don't remember if it's "epic" per se, but my Humanities Professor described it as the Free Bird of classical piano.

Anything Glenn Gould? I don't know much about classical music, but I don't see why his work wouldn't be considered "epic," so...

Thanks for all the suggestions. Also, I must add that while I enjoy the sound of most classical music, I'm not very knowledgable about the subject, which I guess is the main reason why I had to ask for suggestions. Anyways, I'll have to check those suggestions out, although it'll probably have to wait until next week...stupid final research paper.