Every scene in Les Miserables. It was the first show I saw on Broadway and I had no idea anything on stage could do all that. I still find it breathtaking.
Transition from Old Joe to Young Joe during Goodbye, Old Girl in the 1994 revival of Damn Yankees.
The house in An Inspector Calls.
Act I finale in Lord of the Rings (probably the most unbelievable effect I've ever seen on stage).
The Fall of Saigon in Miss Saigon.
Custer's Last Stand tableau in Will Rogers Follies.
Car in Chitty Chitty Bang Bang (much more so than Mary Poppins flying).
Fountain in Bombay Dreams.
Lighting carousel and cyclorama in Jane Eyre.
Circle of Life and Stampede in The Lion King.
Defying Gravity in Wicked.
The dove during Love Me in Two Gentlemen of Verona.
De La Guarda - Entire show.
Fuerza Bruta - Treadmill and water dance.
Revolve in the London production of Cats (totally wasn't expecting it).
Solidarity and We'd Go Dancing in Bill Elliot.
Waiting For Life to Begin and Rain in Once on This Island.
Movie screen framing device and color/b&w transitions in City of Angels.
Mama, I'm a Big Girl Now set in Hairspray.
Motorcycle/Train sequence during A Kiss is a Terrible Thing to Waste in Whistle Down the Wind.
"What can you expect from a bunch of seitan worshippers?" - Reginald Tresilian