There are tons of others I think are great, but I'm only putting down ones that I feel have a message, or define our culture, etc.  Oh, and these aren't in any real order, either.  I could only fit 7 on this page, but I can easily come up with more.

The classic trilogy's films are phenomenal.  The newer ones aren't up to the caliber of the others, but they should still be seen anyway.

At the time I'm writing this, the third one has yet to come out (by 3 days), but the other 2 are excellent, and I expect the final one to follow suit.

A truly beautiful film.  Movies don't make me cry, but if they did, this one would.

This isn't about the battle of Gettysburg.  It's about the people involved and the effects the battle has on them.  A truly wonderful film, but not for those with 5-minute attention spans.

The powerful true story of a concert pianist in the Warsaw Ghetto during the Holocaust.  Truly a work of art.

Classic film.  Stay away from the colorized version and/or the remake.

Awesome movie, we watch it every Christmas season.