I recently picked up Titan AE for about $6.00 at Target and was surprised that it was a really nice looking and great sounding movie. Die Another Day was another good one if you do not like animation. Actually, the list is long and full of variety.
I watched A bug's Life over the weekend. I had forgotten how fantastic the sound for this movie is!! Great use of directional audio. There are plenty of movies made that ignore the subtle directional sounds. It was a pleasure to revisit this movie.
other great sounding movies: U-571 Desperado Daredevil The Haunting
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.