Thanks for your fave on my Bielsky wallpaper! As war movies go, that one's not bad. If you liked Defiance, try Schindler's List or The Great Escape. The original Bridge on the River Kwai is pretty funny to watch nowadays since it was made like 60 years ago. I noticed you like war movies.
Another war movie, not necessarily about WWI itself, but is REALLY good and interesting to see, is Joyeux Noel. It takes place during Christmas, but it's so good it doesn't matter when you watch it. Really well made.
Sorry, I kind of went on a rant about movies. I do that.