With 'American Beauty' the one thing that I always remember from that movie, based on the great ending was the saying "You are what you hate". It's so true sometimes!
I love the endings to Memento, The Usual Suspects, and The Sixth Sense. I didn't like the ending of Identity, though. I don't want to spoil it for anyone, but I thought it was kind of stupid. I thought it would have been cooler if they'd somehow come up with a...different...way of explaining the murders.
Man, I freaked out when I first saw Memento and it ended. I was like...WTF? And I woke up my friend who'd seen it before (we were watching it at like 2 in the morning) and she had no clue what I was going on about.
My favorite surprise ending has to be "Sleepaway Camp". That is one of the most surprising ending ever in a horror movie and to this day I still get a little bit surprised whenever I watch it w/ anyone who has not seen it. It's just a classic and it's so great.
I agree with Identity, Memento, and The Others. I also liked the ending for Se7en. Didn't see that coming...or maybe I was too into the story to think clearly that eventually something like that would happen. :lol: