Based on both food and atmosphere togethere.
MK - Liberty Tree
EPCOT - Chefs du France (bistro may be better, I have not eaten there)
DHS - Brown Derby
AK - Tusker House
In MK it came down to CP and LT. LT gets the nod because it's table service. When taking into account atmosphere, someone serving me food wins over me getting it myself. Getting plated food (as opposed to family style) is even better, but the plated meals at Tony's does not make up for the lacking food.
EPCOT - Most places have decent food. France has atmosphere.
DHS - Brown Derby, hands down
AK - I just really did not like the service at Y&Y or the food itself. I may give it a second chance somday, but for now it dwells at the bottom of my list.
As others have said, there are much better places in the various resorts.
-dave