Best Movies of All Time?

I know we all have our favorite movies. But the classics remain the same-at least on my works website :) But I do think that a challenge is in order. Can you guess the top ten movies of all time? I bet you can name a few, but how about 10?
I'm sorry but I really don't feel like naming the answers right now. If I'm feeling particularly nice, I might list them tomorrow. In the mean time guess away!