There are actually quite a few I haven't seen that I get the "OMW you haven't seen that?" reaction for, so I might not have seen all of my recommendations. Anyways:

- Hitchcock stuff - The Birds, Vertigo, Rear Window, etc
- Psycho
- Donnie Darko
- Any National Lampoon Vacation movies (though Christmas Vacation is the best and best known, I think)
- Back to the Future
- Gone With the Wind
- Casablanca
- People say you should watch Lawrence of Arabia, but after watching my roomie watch it, I would actually recommend skipping it. |D
- The Godfather
- Pulp Fiction

That's all for now, but I can ask my film buff roomies and see what their recommendations are. |Db