I don't really watch a lot of war movies. But there are a few that I watch and re- watch.
La vache et le Prisonnier with Fernadel and La Grande Vadrouille with Louis de Funès & Bourvil because they are lovely memories of watching with my dad and laughing our heads off.
Other films are:
Der Untergang
Het verdriet van Belgie
Zwartboek
Le Toubib
and then the english spoken
Operation Petticoat
The Patriot
Von Ryan's Express
The Great Escape
The Wild Geese
The Sea Wolves
Escape to Athena