For general, good-time, fun Army fiction, try the "Brotherhood of War" series by WEB Griffin. Starts with "The Lieutenants" and follow a group of officers and their families through their careers. Starts in WWII and ends with Vietnam, if my memory serves me. There are a dozen or so books in the series, and this group of guys always seem to be in combat and at the forefront of any new Army trend (ie: tanks, aviation, Special Forces, helicopters, etc...). The series is very entertaining, and you really get to love the characters. Leadership and Army / military history more than any particular small wars, though Vietnam and Congo play key rolls in the later book. I read the series while deployed in Iraq, and they were a good escape. Worth the time if you have it.

For our Marine brothers, Griffin also has "The Corps" series. I got about half way through those, but got sidetracked. Focuses on pre-WW2 - WW2 Marines. Also great reads, especially if you're a WW2 buff.