A number of the war movies I like are on the backdrop of a war rather than movies about the actual fighting. Some of the blood and guts films are great too but since these sort rarely get a mention I thought I would mention some of faveorite 'war as a back drop' movies.
Ice-Cold in Alex -
http://www.imdb.com/title/tt0053935/
Lawrence of Arabia -
http://www.imdb.com/title/tt0056172/
A Matter of Life and Death (called Stairway to Heaven in the USA) -
http://www.imdb.com/title/tt0038733/
Hope and Glory -
http://www.imdb.com/title/tt0093209/
As actual war type movies go don't forget The Dam Busters