Many good books already listed, let me drop some of my fav's.
Armor by John Steakley
Moreau series by S. Andrew Swann (Emperor's of the Twilight, Forests of the Night, Specters of the Dawn)
Marid Audran Trilogy by George Alec Effinger (When Gravity Fails, A Fire in the Sun, The Exile Kiss)
The Hope Series by David Feintuch (Midshipman's Hope, Challenger's Hope, Prisoner's Hope, Fisherman's Hope, Voices of Hope, Patriarch's Hope)
Honor Harrington Series by David Weber (On Basilisk Station, The Honor of the Queen, The Short Victorious War, Field of Dishonor, Flag in Exile, Honor Among Enemies, In Enemy Hands, Echoes of Honor, Ashes of Victory, War of Honor)
The Heritage Trilogy by Ian Douglas (Semper Mars, Europa Strike, Luna Marine)
Grunts by Mary Gentle
Mordant's Need Vol 1-2 by Stephen R. Donaldson (The Mirror of Her Dreams, A Man Rides Through)
The Fuzzy Series by H. Beam Piper (little Fuzzy, Fuzzy Sapiens, Fuzzies and Other People, Golden Dream: A Fuzzy Odyssey)
The Quarters Trilogy by Tanya Huff (Sing the Four Quarters, Fifth Quarter, No Quarter)
Illusion by Paula Volsky
Snow Crash by Neil Stephenson
This is just a small sampling of the Sci-Fi and Fantasy novels that I like to read. So much so that I read all of them over and over. Hope this list gives some of you a few good ideas. And if anybody has any questions about any of the books on this list, I would be glad to answer them to the best of my abilities.