What Is the One Movie You Absolutely Must See in a Theater?

There are plenty of amazing movies out there that can be appreciated on a screen no bigger than your tablet. But others really have to be seen in a theater, preferably with a huge screen, in order to be absorbed fully. Which movies require the theater treatment?

Tell us which movie you would always recommend that people see on the big screen, and why. Is it about the visuals? The sound? The experience of being immersed in a story while in cavernous, dark auditorium?

My pick is Inception, but not just because its visuals are absolutely stunning. What's important is that the images in this film are designed to invoke the power of enormous places like cities. You can't watch a city fold itself up on a small screen and feel the total grandeur of what's happening.