One of my favorites is The Hobbit. It's not primarily about death, but it has a lot of very thoughtful ideas about mortality and the utter foolishness of war. Among my best-loved bits is the parting between Thorin and Bilbo:
"Farewell, good thief," he said. "I go now to the halls of waiting to sit beside my fathers, until the world is renewed. Since I leave now all gold and silver, and go where it is of little worth, I wish to part in friendship from you, and I would take back my words and deeds at the Gate."
"There is more in you of good than you know, child of the kindly West. Some courage and some wisdom, blended in measure. If more of us valued food and cheer and song above hoarded gold, it would be a merrier world. But sad or merry, I must leave it now. Farewell!"
-- Thorin Oakenshield in The Hobbit by J.R.R. Tolkien