One of many excellent tracks from the Invincible album which I highly recommend (buy it here). The work of this production company covers a wide range of musical tastes suitable for epic fantasy, but is particularly useful for action scenes.
A Celtic Journey by Peter Crowley Fantasy Dream
This selection comes from the album Legend of The Dragon (purchase it and other works here). Anything put out by this company is highly recommended. Most fantasy fans are at least partially familiar with Celtic or Celtic-like music, and so this album is excellent for setting a mood for a fantasy game or story.
Music from Ancient Rome by Synaulia
Synaulia is a team of musicians, archeologists, paleorganologists and choreographers dedicated to the application of their historical research to ancient music and dance, in particular to the ancient Etruscan and Roman periods. This is excellent for older cultures (such as Elves or Giants) in a fantasy setting.