All of the movies mentioned here are pretty good, some are very good. But
"Saving Private Ryan" took the standards for realism in war movies to a new level.
"Band of Brothers"
took that level and expanded it into ten hours of true stories about the 101st Airborne, from basic training, to jumping into Normandy on D-Day, to the seige at Bastogne, to Hitler's Eagle's Nest at the end of the war. It has to be the ultimate and best of WWII movies.