Admittedly, it's an impossible question for a person like me who views, on average about 200 movies per year, but people (students especially) ask nonetheless, "What's your favorite movie?"
So perhaps my choice is a bit weasel-y, because it is an Official Recognized Classic. But once one considers the complete and utter destruction of human life due to male pride and vanity, what other response is possible, but laughter? So Dr. Strangelove is, theoretically, that most perfect of comedies--one that makes you laugh to (and at) death.
Thus, In The Loop (2009) sneaks in the side door of catastrophic satire. Presidents, Prime Ministers and Premiers are banned from the landscape, and our gaze is not permitted to go any higher than the sight of cabinet officers, their minions and enforcers. (In fact, the film suggests that critical policy is set without the knowledge or consent of elected officials.) The story, in a nutshell, is that of Britain being dragged into an American incursion in the Middle East primarily due to the thoughtless words of a thoughtless Cabinet Minister.
In The Loop even echoes Strangelove's immortal line, "There is no fighting in the war room" with a tense negotiation taking place in the meditation room at the UN. This setting is evidently based on fact as told to the writers of the film. According to the director, at the end of a screening of In The Loop to a group of Washington insiders, one of them raised his hand and said, "Can we just say we're sorry?"
Watch it and laugh--if you can handle the truth.