For Magic Kingdom-
Tortuga Tavern is my favorite QS location, but it's hardly ever open. Their taco salad is delicious! Be Our Guest is top-notch when it comes to QS locations, but only for lunch. They've got amazing sandwiches and offerings like quiche, not to mention "the gray stuff", but it can be hard to get into. Pinocchio Village Haus and Cosmic Ray's are two other QS locations that are open for lunch and dinner and serve conventional food (hamburgers, nuggets, etc.) The only time I ever had a QS breakfast in MK was at Gaston's Tavern and it was okay- it's great if you like the cinnamon buns in the park! And Lefou's Brew is delicious
For Epcot-
The Land has a really good QS restaurant with a highly acclaimed strawberry shortcake dessert. Really, whatever kind of food you're in the mood for, you can find it in the world showcase. The fish and chips in United Kingdom are always a favorite, though
For Disney Hollywood Studios-
DHS is a big mess when it comes to QS locations, there's very few of them and some of them (i.e. pizza planet) just aren't good. The ABC Commissary is supposed to be the best.
For Animal Kingdom-
There's plenty of great QS locations here. Flame Tree BBQ and Yak and Yeti are my favorites
The ribs at flame tree bbq are things of legends.