Your bookshelf is a good indicator of who you are. I'm always fascinated to look at a bookshelf when I visit someone. It tells you so much about them.
But also, the movies you like say a lot. Movies are a wonderful thing. There is the "they are made to make money" component of them. But they can say a great deal about the world, and move your heart.
Obviously, these things change from day to day, but here's my favourite 20 odd :
The Andromeda Strain.
20 Minutes into the Future (UK version).
Hudson Hawk.
Crimson Tide.
Slipstream.
Enemy Mine.
Solaris.
Heathers.
Soylent Green.
2001.
Rocketeer.
Dr. Strangelove.
Flash Gordon.
Akira.
Gattaga.
Porko Rosso.
THX1138.
Tank Girl.
Logan's Run.
Millenium.
Bill & Ted's Excellent Adventure.
Silent Running.