Most if not all of my favorites have already been listed, but I think Hamburger Hill comes as close to the raw emotion most of who've "been there" have experienced.
A very good, but rarely seen flick is
The Bridge.
"Near the end of World War II, a small German town braces for the onslaught of American troops. Eight schoolboys are conscripted into the army and their first order is to defend a bridge leading to their town."