Now I know it's hard to pick just one, so let's break it down into categories.
Feel free to add your own category, as I'm gonna stick with these.
Drama - The Shawshank Redemption
Action - Boondock Saints/300/The Departed (I can't decide!)
Comedy - Grandma's Boy
I would've added chick flicks and horrors, but I'm not too big into those, but go right ahead!