Pizza - Napoli in DTD is the only place I ever eat pizza at DL. Not because I love it so much, but because I just don't think of pizza when I'm in DL. There's so much other unique stuff.
Sandwich - Monte Cristo at Blue Bayou, although it can sometimes be disappointing. I also used to love the Fried Green Tomato Sandwich which used to be at Hungry Bear .... I know it went somewhere else but don't know if it's still there or not.
Taco - Street Tacos at Cocina Cucamonga in DCA
Ice Cream -- I don't remember what it's called, but Ghiardelli in DCA has a raspberry/dark chocolate thing that's to die for. Def my fav unless you count Dole Whip. I also love the Mickey ice cream sandwiches and bars.
Non Churro Sweet Snack -- It's simple, but there's nothing better than the fresh pineapple on a hot day. Raspberry Rose Macaron at Jolly Holiday
Non popcorn salty snack -- Pommes frites at Cafe Orleans.
Best candy -- English Toffee -- I know they have it at DCA and I think at Pooh's Corner in DL as well
Soft Drink -- Red's Apple Freeze at Cozy Cone in DCA or Rose Petal Soda at Carthay Circle
Don't drink beer
Best adult beverage -- Anything that comes with one of those little light-up ice cubes

Or anything from Trader Sam's
Two things I don't see a category for that I have to have every trip: Bacon Wrapped Asparagus at Bengal BBQ and Chili Con Queso at Cozy Cone