Just finished Gates of Fire by Steven Pressfield, and if you haven't read it, I highly recommend it.
It's historic fiction, the story of the battle of Thermopylae where 300 Spartans and their allies sacrificed their lives to stem the advance of the 2 million man invading Persian army. As history shows the Spartans were killed to the last man, but they slaughtered thousands of Persians, delayed their advance for three costly days and inspired the Greeks to achieve victory by their example.
The book's strengths are the scenes of combat, where you gain a whole new appreciation for the grim struggle of heavy infantry, clashing with spears and shields, as well as the depiction of Spartan culture, which from birth breeds men willing to fight and die for their homeland. They were the greatest warriors of their age (and perhaps any age), not only because of their rigorous training but because they conquered the fear of death.
Through it all, Pressfield makes you care by creating vivid, memorable characters. I can't say enough about this book!