MK - Dole Whips
Epcot - egg rolls from China, anything from the bakery in France
AK - fruit or veggies from the cart in Africa
MGM - haven't found anything special here...yet
The root beer floats are in Dinoland at AK...a small stand next to Donald's Restaurant (Breakfastasaurus). It's a great treat, plus you get to keep the cup and the reusable Mickey straw (no disposable straws at AK so there's no harm done to the animals).
Some of our favorite treats are:
Mickey Premium Bar
Dole Whip
popcorn
Kaki Gori (Japan's version of a snowcone)
White chocolate macadamia coconut cookies
The HOT GLAZED PECANS at Epcot. By the way they can be found at a little cart in front of American Adventure. This is a must have for our whole family every trip.
I had a slice of chocolate cake that was to die for in Dec 99 at Main St Bakery that they havent had on trips since then. If somebody is there in the World and reading this and they have that Chocolate layered cake with chocolate icing please send me a piece.
I know it's not exactly in the parks, but we have been known to nip out to Boardwalk from World Showcase to nab a lump of crumb cake from the bakery there.
And as for in the park... it has to be funnel cake! I love that stuff, can't get it here in the UK, so I always have one at EPCOT and another at Blizzard Beach when we go.
Since the bakery at the Boardwalk was mentioned I gotta say we love the pecan sticky buns. The first time we had them was at the food court at Port Orleans .
A year later we went back and they weren't selling them anymore. Boy, were we disappointed.
Luckily, later that day we went to the Boardwalk and found them at the bakery. We make it a point to have them everytime we go to WDW. Patty