we'll keep this one stickied so that all the movie buffs can enjoy/add to
Clerks
Plot: A day in the lives of two convenience clerks named Dante and Randal as they annoy customers, discuss movies, and play hockey on the store roof.
This is one of my favourite movies, arguably the best small budget movie made big. The argument over the merits of blowing up the Death star in star wars has to be one of the best bits of scripting. Likewise the guy blagging some quality toilet paper and a porn mag so that he can go for a wank in the toilets.
Rating: 10/10 - they dont come much better than this