Given the history of Man is a history of war, the number of war movies is astounding. The cinematic treatments of WWII alone is beyond count. You could make a list of ten magnificent "POW" movies from WWII.
That said, I will list of ten of my favorite war movies, because after all it is my blog. I know I will be scorched in the comments for leaving of many classics.
In no particular order:
Battle of the Bulge
Full Metal Jacket
Pork Chop Hill
Waterloo (the Sergei Bondarchuk version with Rod Steiger as Napoleon)
In Harm's Way
The Fighting 69th
Saving Private Ryan
I am sure you have favorites. Let me know what I missed in the comments