Yeah, this topic does need some defining of terms. Having battle scenes - therefore being more of a war film than a wartime drama - is a good distinction YG.
Battle of the Bulge is one of the least historically accurate and has probably the most generalized plot based on a historical event that I have ever seen. That said, I love the movie. The action is quite good, the scale is huge and the actors are great.
It is a minor travesty that these two are not yet on your list:
Patton - with how universally lauded and awarded this film is, it is an automatic and permanent inclusion in the top 10 of all time.
Midway - I personally think this movie is excellent and the great use of real battle footage helps seal the deal. Fortunately my dad was able to tape it when it came on TV, so I got the pleasure of always watching the movie with the Battle of the Coral Sea included. It is simply not as good of a movie without that in it.
Maybe we can nominate Christopher Nolan’s new film prematurely? While I have never thought the Battle/Retreat at Dunkirk to be as compelling as other aspects of the war, I am sure Nolan will easily make it into an excellent film.
Oh yeah… how could I begin to forget:
Kelley’s Heroes - No reasons required.
Okay another glaring omission:
A Bridge Too Far - This may be the biggest and most ambitious WWII film ever made. The legendary cast alone is ridiculous.