no one movie does it for me. Its mainly due to the fact that I'm very, VERY, critical of not just movies but all forms of media I go to for enterainment. I read a lot, watch a lot of tv and film and I played just about every major game prior to the release of the 360 and PS3, mainly cause i ran out of money to buy them.
There are plenty of films that have such meaning in them you can't help but love them
American History X
Full Metal Jacket
End of Evangelion
Seven Samurai and Samurai Seven
Casablanca and plenty of other films strike a cord in me. This includes Clerks but thats because I know what it means to work behind the counter.
Most mind blowing movie I've ever seen? two sets of Anime. Puni Puni Pomei, by the creator of excel saga. Also the Golden Boy series of OVAs.