Define "best".
There's lots of bad movies with great audio and video...
Twister is a prime example. I don't think
Fantasia/2000 is a "great" movie per se, but damned if that DVD doesn't deliver some of the best aural and visual goodies you're likely to ever find on a DVD. The audio is taken for granted because it is made up of music, and therefore lacks a lot of split surround f/x (although it does have those too in certain moments) -- but the moment in
F2K where Mickey Mouse runs around the room looking for Donald, his voice jumping from speaker to speaker to rear speaker to rear speaker to front speaker again, is always how I choose to first show off my home theater to relatives and friends.
If you want a *great* movie with *great* audio and video, that narrows the field considerably.