The pod race scene in Episode I is a given, but make sure you play the THX intro at the beginning, it's amazing. Soft rain, like something you'd hear under a porch, soft but very enveloping, comes from the QS8s while you hear the sound of thunder from inside a glass sphere from the fronts. BAM, lightning hits the sphere, it explodes, and suddenly you're an open plain and the storm is rolling over you. Then the pieces of the glass ball come togther to create the THX logo and that THX sound fills the room. AWESOME!
Also, Toy Story 2, at the beginning Buzz is flying around the planet in the video game with his jet pack and he drops into a canyon. The camera position shifts to behind Buzz as he flys along and the sound moves to behind the listner - very cool effect.
