I have two areas of nostalgia, when I was a kid and with my kids.
The Former is Cranium Command, Land Pavilion with the balloon dudes, Veggie Veggie Fruit Fruit, and the old Tiki Room (with a subtle add of the old gift shop in Adventureland with the tropical attire).
The Latter is based on experiences so when they change or get iced, it will hit me hard. The are The Magic Carpets (based on a trip with my 3 year old at the time), Rafiki's Planet Watch, Aerosmith, and the Star Tours Gift Shop.