What's a Perfect Movie?

I'll tell you one: Rosemary's Baby. Just like Kelly Ripa, the 1968 thriller doesn't have one ounce of fat on it. Every frame packs a punch as you learn of Rosemary's growing horror as seen through her own eyes. As she realizes her husband's sold her body to the devil, so do you, and it's all done with suggestion, psychological insight, wicked humor, and spot-on casting. I couldn't think of a single way to improve on this movie; you just want to watch it again and again in awe--and I do, thanks to various cable channels.

Any films you feel that way about? Which flicks are pure perfection?