Hollywood has been, nearly since inception, a way for America to showcase and treat its own historical traumas. The movie industry never wait too much before they surf on terrible events and make them subjects for films. No taboos are allowed. And the American people rush to see them just like a big therapeutic session as if they were long gone.
Think of all the westerns of John Huston or Sam Peckinpah, the uncountable movies on the second world war (which is still a hot matter: watch upcoming Valkyrie) which were very popular at the time and then the Vietnam War (Full Metal Jacket is a must just like Platoon or the Deer Hunter) the Gulf War (Three Kings and i absolutely recommend Syriana)
Here are a series of recent good movies that surf on that trend:
September 11: United93 is probably the best movie on the matter and was made only a few years after the terrible events. You can also watch Oliver Stone's Word Trade Center but i do not recommend this. It stinks ketchup and popcorn too much
Afghanistan/Taliban: Charlie Wilson's War is probably the most notable movie, But i would recommend to see the Kite Runner which as a movie is more touching. Recently there was also Lion for Lambs with a great casting (Cruise, Redford, Streep) but a poor story
War in Iraq: I recently saw 2 good movies on the subject in very different styles. The Kingdom is an action movie which is well done and well executed. But the most touching is certainly In The valley of Elah by master Paul Haggis (Behind Crash and Million Dollar Baby) with the story of this father inquiring on the disappearance of his son.
Do you see more? What is the next big trauma hollywood is going to transform in a Movie?