Amigo... after a long loooooong screening of Dr. Zhivago (197 minutes), I've started paying more attention to the actual length.
Picking from the films that people have listed and bringing in a few quirky ones of my own (with the total confession that I only know what I like):
The African Queen -- the dialog is so great
Free Script Here
Aguirre, the Wrath of God -- two scenes make this film -- my introduction to real history and Klaus Kinski
A Christmas Story -- "You'll put your eye out!" Americana at its best
The Good, The Bad and The Ugly --- the music, the justice
Medicine River (which I love and nobody else gets) -- the calm & the pauses
Monsieur Ibrahim et les fleurs du Coran -- circular, fulfilling, Omar Sharif
My Fair Lady -- the music, the clothes, the story
Singing in the Rain -- Gene Kelly's dancing
The Sound of Music -- the kids, the scenery
The Tao of Steve -- the philosophy
I'd also add Amelie, PowWow Highway, Scrooged, Forrest Gump, 2001, Apollo 13, Pulp Fiction, Roxanne, Shawshank Redemption, and several other films I'd willingly watch over and over. Plus there's One the Movie, which has not yet been released. I loved One.