Kingdom of Heaven wasn't a bad war movie (not modern, of course, but the topic, The Crusades, was quite interesting).
If you're looking for a good WWI film, then I'd suggest you check out
The Lost Battalion. Not many others have come out which instantly come to my mind.
Der Untergang was actually the last World War II film I've seen in ages.
It seems like Hollywood is cutting down on the World War films that are made. Sad, too. Although Steven Spielberg is planning a new miniseries like
Band of Brothers, only set in the Pacific Theatre for HBO (loathsome channel which is practically just porn; nothing tasteful IMO).