There are a few movies that have had an impact on how I view various issues, such as Jean Renoir's "La Grande Illusion", which, among many things, shows that national identity can be determined by an imaginary line between two nations, and Gillo Pontecorvo's "La Battaglia di Algeri", which, to me, shows how people can react to a occupying force.  Although this movie is about Algeria's fight for independence from France, it's also a good analogy of US forces in Iraq.