Top 5 (for right now):
LOTR (I count the 3 as one movie...best ever!)
Forrest Gump
Braveheart
The Breakfast Club
Donnie Darko

Very honorable mentions:
Pulp Fiction
Unbreakable
Equilibrium
Almost Famous
Star Wars Episodes IV, V, and VI
Lock, Stock, and Two Smoking Barrels
Snatch
Fight Club
There's Something About Mary
Airplane
Spaceballs
Willy Wonka and the Chocolate Factory
The Neverending Story
Labyrinth