What is a "Perfect" Film You've seen?

Obviously film is subjective and perfection is in the eye of the beholder, but in your opinion, what is your perfect film? Mine has to be There Will Be Blood. Personally, I don't think anything I've seen has been so superb from start to finish.

Edit: Didn't expect so many responses, but I appreciate reading through all the comments. My watchlist just got a whole lot bigger!