The ones ive seen in these choices are saving private ryan, black hawk down, pearl harbor, and a few parts of band of brothers.
I really dislike pearl harbor, the characters were not expanded or looked into, but it did its job as a war flick, to put into perspective what sacrifices men of duty have to make.
black hawk down and band of brothers shows the brutality, realism, and the true side of war, that is what makes them great, but again the characters could be expanded upon.
saving private ryan is one of the best WW2 flicks ive seen, it goes into the emotional conflict and shaping it does to GI's war veterans. The unique and rememberable characters, and at the same time accomplishing to show the true qualities of war.
My vote goes to saving private ryan