I like the Dole Whip Float best. The tartness of the pineapple juice blends so well with the sweetness of the pineapple sorbet.
Other favorites:
Norway: Sweet pretzel with almonds, cinnamon rolls, school bread, and also a combination of their waffle with strawberry jam with rice cream. The two flavors to great together.
Germany: Apple strudel with vanilla sauce
France: Peach tart, chocolate croissant
MK Sweetshop: Carmel apple with nuts (I take it home and cut it into more manageable slices)
Other options:
Soft serve swirl cone at AK
Churros from Mexico
Egg rolls from the carts at MK
Pretzel with cinnamon sugar from Wetzel's Pretzels
Yaki Gori from Japan
Ginger/caramel ice cream from China
I think the rice krispie treats shaped like Mickey with chocolate covering the ears are very popular. You can take it with you and eat it later if not hungry in the parks. Stock up at the end of your trip if you have extra unused credits.