I agree with all of kutchyone's positive recommendations except for the cantina de san angel, although the san angel inn (table service) is nice.
I have to disagree with the comment about Alfredo's, though. We have stayed away from it because of reviews like that one, but decided to give it a try on our last visit simply because it is one of the very few restaurants we have not been to. We were very pleasantly surprised and enjoyed our meal very much. We had an appetizer that had meats, cheeses, and olives that was very good. I had the pasta sampler that had a very good lasagna (not quite as good as mom's) a good penne with tomato sauce, and an exquisite pasta filled with truffles in a sage/cream sauce. The dessert sampler was good, but was not my favorite part of the meal. It was very loud, but coming from an Italian family, I wasn't bothered by it. They also had a funny little accordian player who came through once and played a song.
We love:
Spoodles (especially the mediterranean dips appetizer)
Jiko (kalamata olive flatbread and the chicken entree cooked in a tangine)
California Grille (pork and polenta with mushrooms entree)
Citricos is a new favorite, also..everything we had was great
Le Cellier simply because of the cheddar cheese soup!
Flame Tree BBQ for lunch - favorite counter service meal
Kona Cafe for breakfast - Tonga Toast and Liliquoi juice (sp?)
Beaches and Cream - best cheeseburgers and cherry coke
Kringla Bakery for snack- we love the school bread - coconut cream filled donut type pastry
The Yachtsmen Steakhouse at the Yacht Club is also a very good meal.
If you have to eat in MK (which we try to avoid) we like the Pecos Bill Cafe because they have a condiment bar that includes sauteed onions and mushrooms to go with the burgers. They also have a nice looking (haven't tasted it) salad, or we also like the Liberty Tree Tavern. Cosmic Ray's would be in 3rd place.
I"m sure I'm forgetting something, but these are the most important. That's the thing about Walt Disney World, though, there are so many choices for so many palettes.
Happy Eating!

Minniegrl