MK: Starlight Ray's (in tomorrowland) get the half chicken & ribs meal, tons of food
Epcot: Sunshine Seasons (in the Land), anything you want, they have
AK: Flame Tree, tons of food and yummy BBQ
DHS: The one in the back, past the Jedi training (NOT the Pizza place); this one has th best sandwiches.
Given all service is equal in Disney, these are the top ones I like in each park.