The Enemy Below, submarine/destroyer heroics between Robert Mitchum and Curt Jurgens is very entertaining and also shows the emotions of war from both sides.
http://www.imdb.com/title/tt0050356/
There was a film I was trying to remember and I just did now. It's The Rakes Progress starring Rex Harrison. It was made in 1945 so it might seem old fashioned but I'd like to see it again.