Clerks - the first time I saw this was on MTV and I was blown away by it. Before the word MTV here scares you off, it's the exact opposite of anything you'd expect on MTV. Clerks 2 on the other hand, would fit the channel.
The Good, The Bad and the Ugly - Classic in every way possible. It was a theaters here a few months ago, went and saw it. One of the best things I've seen in theaters, and that includes Lord of the Rings.
The Shawshank Redemption - If you:
A) Do not like this movie
B) Haven't see it
You're dead to me.
Tampopo - Japanese movie about ramen. Hilarious, well written and loveable characters. Doesn't go too far over the top like most Japanese movies do at one point or another.
The Incredibles - The best CGI movie since Shrek, in my opinion nothing has come close to how fun this movie is in a long time.
Lock, Stock and Two Smoking Barrels - Can't really say much about it, besides the fact that it's great. If you've seen Snatch, it's like it but it has a bit more character I find.
Dogville - Not that well known. It's filmed on a stage and takes place in a town. There's lines on the floor to show where the houses are and people act as if they're really in a town, opening doors, moving things out of the way, even though there's nothing there.
It's a really dark and depressing movie though.
This is the town, in case anyone is wondering:
http://www.maxmarkel.com/blog/wp-content/uploads/dogville-grundriss2.jpg