Oh gosh, wonderful question, and I’m sure you will get tons of different answers.
MK . . . we like the Pirates game, love sitting and playing a game of checkers with my son outside the candy shop in Town Square. We love riding the Haunted Mansion way too many times lol. People mover after dark is awesome. Love riding the train around the park, and catching a ride on one of the main street vehicles in the morning. We love to watch the piano player outside of Casey’s, ride Big Thunder after dark, and climb to the top of the Swiss Family Robinson Treehouse (great views, awesome for taking pictures of the park). We love to start our day with a breakfast at Crystal Palace. Supper at Liberty Tree Tavern is a joy too.
AK there are so many new things. Flights of Passage is breathtaking. Na’vi River Journey is simply beautiful, and Pandora after dark is amazing. The Safari is great, both during the daytime, and during the evening. Festival of the Lion King is, in my opinion, the best show in any of the parks, and a must do. The birds of prey show is fantastic. Flame Tree BBQ is perhaps the best quick service restaurant in Disney World.
EPCOT The big three rides, Test Track, Soarin’ and Frozen Ever After. Spaceship Earth is a favorite, and pretty much all kids love the Turtle Talk with Crush show. Snacking around the World Showcase, enjoying a taste of each country along the way. We love the outside seating areas up near the quick service restaurant in Japan. It is a quiet area, out of the crowds, beautifully landscaped, with some shade. It is a perfect place to enjoy lunch, or just a drink or snack. We also love the food at the Rose and Crown, and bonus, if you can get a dinner reservation for around 7:30, and ask politely if it is at all possible to get a seat outside . .. . it is the perfect place to sit and enjoy your meal, and if you take your time a bit, you will be eating desert while you watch Illuminations from your table. This is our absolute favorite way to end the day at Epcot, followed by a slow leisurely stroll out of the park.