Frost/Nixon
Thanks to the skilled direction of Ron Howard and the extraordinary acting of both Frank Langella and Michael Sheen, this is the best exploration of the workings and motivations of a U.S. President that I have ever seen.
Moon
Moon is currently available in select theaters via limited release (I was lucky enough to catch it in NYC last weekend), but if it shows up in your town–or anywhere close to it–make the pilgrimage. Thoughtful, character-driven science fiction has returned.