This is a split from the other epic threads (the first (http://www.indie-rpgs.com/viewtopic.php?t=10290) one, and the one on abilities (http://www.indie-rpgs.com/viewtopic.php?t=10377)).
I want to suggest that, when defining "epic" for the purposes of an epic-emulating rpg, there is a "sweet spot" between defining epic narrowly as "poems of a certain form which recount the deeds of heroes in an elevated style" and broadly as "anything that has the intangible feeling of vastness, grandeur, or excitement associated in ordinary language with the word 'epic'."
The sweet spot is found by using epic poems as a base for the definition of epic, but then extending the definition of epic to subsequent literature which resembles the actual epic poems in certain crucial respects.
I may be stretching, but the Elric saga strikes me as epic in the latter sense. It does not at all fit into the epic category of literature. It is modern fantasy or swords & sorcery (or whatever people are calling it these days.) But, Elric is a hero with a tragic flaw, who combines great puissance with equally great passions, and with a weakness that nails him in the end.
(While Elric might strike some as an anti-hero designed purposefully to subvert more traditional epic-style heroes, recall the anti-hero aspects of the archetypal epic heroes Achilles and of Odysseus. Achilles is a wraithful, arrogant, bloodthirsty maniac--as opposed to the more "responsible" Hector. Odysseus is the master of devious, sometimes under-handed strategems--the epitome of the "treacherous Greek" stereotype of the ancient Romans (cf. our medieval and modern "sneaky Arab" stereotype)--as opposed to Aeneas, who is the more transparent, chivalrous/valorous sort of hero. The point is, there's room in the epics for the likes of Achilles and Odysseus, as well as the more apple pie Hector and Aeneas. [This overly-simplifies things, but hoepfully you get my point.])
The idea is, there are works of literature outside the strict definition of epic, which might still be taken as source material for an epic rpg--i.e., as characteristic of the sort of material which the rpg is supposed to allow you to "emulate" (whatever that means; that's a topic for another thread, I guess). At the same time, the definition of epic must be sufficiently strict so as to exclude other works of literature which don't sufficiently resemble the epic poems. (If Piers Anthony counts as epic on our definition, we know we're in trouble.)
Rexfelis
[edited to add links]
I'm going to suggest that arguing over whether a specific modern work constitutes an epic before arriving at a definition of epic is a short road to nowhere. I would suggest a better start would be made by listing a number of unequivocal epics and suggesting common links. For the sake of facts over speculation I'd suggest not listing works widely considered to be epics that you personally are not familiar with.
For example:
Paradise Lost
The Iliad
The Odyssey
The Inferno
A sustained narrative consisting of episodes connected through their central characters.
The central characters are epitomes - they are not necessarily supernatural but they do represent the pinacle of something (Satan - evil; Achilles - martial prowess; Helen - beauty; Odysseus - cunning).
The characters are complex - we see both their successes and their failures; their strengths and weaknesses
While we consider them works of fiction, the authors and original audience considered them at least based on fact (e.g. the Divine Commedies are satire and not a literal depiction of Hell but the audience was Christian - the Devil and Hell are real places).[/list:u]
Obviously this last one is the most controversial when applying it to modern works. The counter argument is an unequivocal Epic which does not possess this trait.
An epic can also be defined by following the major corresponding events in most Myths and other epic stories. In epic myths you can usually find a great tragedy in the lives of the main characters, a maiden being stolen away, a death in the family, usurpers taking the throne, and others like this. Then the story follows the main characters through major conflicts of various types, mental, physical, and spiritual, and then at the end of it all usually the heroes come out on top and have finished their quest or in some cases go down in an amazing blaze of glory and honor.