I'd have to break it into 'Holidays'
4th of July: The Patriot/Drums Along the Mohawk
Halloween: War of the Worlds (1954), Hocus Pocus, The Thing (1950's version) It's the great pumpkin charlie brown
Christmas: White Christmas, Christmas vacation, (Is Charlie Brown Christmas a "movie")
Of course while D-Day isn't a holiday, I must watch: Saving Private Ryan, The Longest Day, and Day of Days from Band of Brothers