The caramel popcorn at Big Top Souvenirs. Not the pre-packaged stuff, but the freshly made popcorn. Now I regret giving my daughter the rest of the bag for her to take home.
As much as I love the Dole Whip float (I go orange whip in pineapple juice) and the Mickey ice cream sandwich, I would have to say the cinnamon roll at Gaston's. It is huge, but not heavy, so it isn't over sweet. I'm not a coffee drinker, so I pair it with chocolate milk.