I'll list up to 3 things per park (thats as far as I can narrow it down lol.)
Magic Kingdom:
BTMMR, Jungle Cruise (Corny but funny!), Splash mountain
We enjoy the shops here as we are a bit old for some of the rides.
EPCOT:
Japan and China giftshops, Soarin', Test Track
My mums fave (Cant pick one myself!

)
Disneys Hollywood Studios:
Indiana Jones show, Lights Motors Action, It's traditional for us to eat at Backlot Express.
Great shows here. Beat out even the rides (still v good) IMHO.
Disney's Animal Kingdom:
Kali Rapids, The bird show (Forgot its name *doh*), Kilamanjaro Safaris.
THe park that gets too bad a rep. Lazy-ish walks with great animals (love the bats!) and some good shows and rides.
So... a short(ish) summary of our must do's. There are many more.