I don't believe anyone mentioned Casualties of War, which is pretty good.
Also, the best war movies ever made....Missing in Action and Rambo: First Blood, Part II. Ok, those aren't that good, but First Blood (the original Rambo) is actually a really good movie.
Other enjoyable war movies that I don't think have been mentioned:
The Patriot (Revolutionary)
The Longest Day (WWII)
M*A*S*H* (Korean....much more cynical than the series)
No Man's Land (Bosnia)