Carousel of Progress (with the Epcot city at the end)
I don't consider the Monorail as a Tomorrowland attraction, since it also has a stop in Downtown Disney, so the three I choose to keep are:
Nemo - let Fantasyland usurp as their attraction.
Now lets get an attraction that visits all the other NEW Tomorrowland attractions, like what the Peoplemover used to do.
Let's also a couple other attractions that are high in the sky, like what we used to have with the Skyway and the Rocket Jets!
Let's also get rid of pizza port, and change that bit of real estate BACK to an attraction!
Can't do only three...Space Mountain, Star Tours, Monorail, and Subs. Not the new Nemoized version, but a newer more adventurous version for the 60th. If the Monorail is not counted - then I have three. If I had a fourth option because of that, then it would be a revamped Autopia.
Space Mountain and Star Tours, the rest are about as disposable as a bag of old diapers.