Not a sweet eater, myself. Obviously, you can get popcorn or a turkey leg from carts in all four parks. Here's a few suggestions from me:
Magic Kingdom:
- Fries from Casey's Corner
- Egg rolls or corndogs from the Egg Roll Wagon in Adventureland
- Giant pickle from the Liberty Square Market
Animal Kingdom:
- Onion Ring basket from Flametree BBQ
- Jalapeno Cheese Stuffed Pretzel from Harambe Fruit Market
- Bagel with Cream Cheese from Kusafiri coffee shop
- Breadsticks w/ marinara from Pizzafari
Hollywood Studios:
- Hotdog from the Backlot Express or Corndog from Herbie's drive in
- Pretzel with cheese from Anaheim Produce
- Italian sausage hogie from Min & Bill's Dockside Diner
- Smoked salmon on a bagel at Starring Rolls
Epcot:
- Brat and a beer at Somerfest in Germany! They also have pretzels.
- Bowl of chili from the Liberty Inn
- Potstickers (or egg rolls) from Lotus Blossom Cafe in China Pavilion
- Beef Empanada with a side of Tostones at Refreshment Port. Also have friend shrimp or a chix sandwich w/ tostones.
- Marinated Olives at the Tangierine Cafe' in Morocco Pavilion
- Quesadillas from the Mexico counter service (whatever it's called now).
- Fish & Chips from Yorkshire County Fish Shop in the UK.