So, you want to put your two bits in, but you also don't want to suffer scorn or snicker: "That idea is so cliche!" "Pshaw, if only he'd read..." "Poor chap hasn't the benefit of a decent education."
Shame doesn't even have to be the primary motivator. For your edification and enjoyment, we have listed several works of relevant prose (and even verse) to help foster a context of creativity and informed discussion. We would not hesitate to encourage you to read them, either as general background for the Halo universe, or simply as great entertainment.
Many books were specifically recommended by Joseph Staten (marked with a 1), Eric Nylund (marked with a 2), Jason Jones (marked with a 3) or Chris Butcher (marked with a 4). Thanks, gents!
- Starhammer, The Vang: Military Form, or The Vang: Battlemaster by Christopher Rowley1, 3
- Songs of Innocence, Songs of Experience, "The Marriage of Heaven and Hell", etc. by William Blake
- Tales of Charlemagne, Arthur, Roland, etc.
- Greek History/Mythos
- Any of the works on the Culture, but specifically Use of Weapons1 and Feersum Endjinn3 by Ian M. Banks
- The first Ringworld novel by Larry Niven1
- Beowulf and other Anglo-Saxon poetry
- Paradise Lost by John Milton
- The Halo novels themselves: The Fall of Reach, The Flood, and First Strike
- Ulysses by James Joyce. Make sure you're ready. Perhaps start off with Dubliners ;)
- The Heechee Saga by Frederik Pohl
- The Moon is a Harsh Mistress by Heinlein ("it contains, among other things, a fascinating relationship between a cyborg and an AI")1
- A good anthology of the poetry of John Keats1 (to unseal the hushed casket of the soul...)
- Ender's Game by Orson Scott Card. There are six books in the series; take your time.2
- Starship Troopers by Robert A. Heinlein2
- The Forever War by Joe Haldeman2
- Armor by John Steakley2
- Marine Sniper: 93 Confirmed Kills (Paperback) by Charles W.
Henderson (the Gunny Hathcock story)2
- Berserker by Fred Saberhagen2
- The Mote series by Jerry Pournelle and Larry Niven3
- The seven historical volumes of Oman's Peninsular War3
- Churchill's memoirs of World War II (who "glorifies the righteous struggle of a reluctant but determined underdog")3
- David Ferry's "interpolation" (as opposed to translation) of Gilgamesh3
- Deepness in the Sky by Vernor Vinge3
- Reality Dysfunction by Peter F. Hamilton3
- Revelation Space by Alistair Reynolds3, though a little bird has told me that all his books are well worth reading.
- The works of Freeman Dyson4 (most specifically, the concept of "Dyson Spheres" and, rumor has it (though I'm not naming any sources), Project Orion)
"And some guilt pleasures" (Nylund):
- Hammer's Slammers by David Drake
- The Cobra Trilogy (The Cobra series) by Timothy Zahn
If that's not enough, check out Bungie's own Guide to Sci-Fi with dozens of inspirations from film, television, and literature.
I also recommend liberal amounts of hot chocolate. Enjoy.