Chalk up another for Das Boot, although it's not really easy to pick just one or two films since there are so many good ones. I also love Tora Tora Tora, the Longest Day and Patton. But then again I have a WWII bias since that was my major area of study as an undergrad. I even took a class on WWII in film and literature one semester (watching movies for credit . . . woohoo! almost as good as my class on sci-fi films.) There are so many interesting possibilities and angles to take here. Perhaps this would be better suited by best WWII film, best Vietnam film, etc. Granted, those are by far the two biggest areas.