The Grand Floridian Cafe is really great. For the most part it's quiet, has a relaxed atmosphere, good service, good, reasonably priced food, etc.
I would also reccomend Kona Cafe at the Polynesian.
I wasn't that fond of Captain's Grille at the Yacht Club, but maybe that's just me.
Honestly, I think any TS at a deluxe resort is a pretty good deal and good food.