Originally Posted by Otto the Otter

Full Metal Jacket (watched the first part every day for six weeks before I went to boot camp)
Blackhawk Down (I can relate, I was there. Lots of action)
We Were Soldiers (One of the best I've seen)
Enemies at the Gates (there's dispute about how accurate the movie is, but it's just plain awesome)
Heartbreak Ridge (Not the best, but Clint's Gunny Highway is an awesome character)
Star Wars (one of the classics. It has War in the name)
Saving Private Ryan (just the opening scene alone is worth it)
Flags of Our Fathers (not a whole lot of action, but still really good)
Behind Enemy Lines (not a true story, but still a good one)
The D.I. (with Jack Webb, an oldie but a goodie)
WWII in HD (not a feature movie per se, but worth watching on History Channel)