Here are my favorites:
Character:
Cinderella's Royal Table Character Breakfast - beautiful restaurant, good food, and princesses (what more can I say?)
Chef Mickey's Breakfast - large buffet selection, great photo ops, and a little more room for over-excited children
1900 Park Fare Dinner - it's been awhile, but I remember it having a good selection of "adult" food (like seafood). Picky younger eaters have the standard hot dogs, chicken nuggets, mac & cheese available
Non-Character:
Mitsukoshi Japan Lunch - prepared at your table, very fresh and tasty, insiders tell me this is one of the *cleanest* kitchens on property. I recommend this for lunch - dinner has pretty much the same menu but costs 40% more
Ohana's Dinner- served at your table family style. Food was better than the luau (in my opinon). They now bring out the jumbo shrimp last in hopes that you've filled up on the other meats, but my husband isn't shy to let them know he wants the shrimp & he wants it NOW!
Whispering Canyon Cafe Dinner - fun atmosphere (not a quiet dinner place by far). Plenty of great food for the price, and all you can drink milkshakes!!! Mmmmm
I have been to other, more expensive restaurants, like Artist Point - even though the food is great; I have trouble justifying paying that much money for a meal so it's not on my favorites list.
I've actually only been to two restaurants that I wasn't happy with:
Donald's Restaurantasaurus Character Breakfast - Dining room layout was a little strange and the food wasn't that great or warm- I've had better free continental breakfasts at the Days Inn
Coral Reef - we went for lunch hoping the price would be reasonable, but it was very high. The cucumber salad I ordered tasted like it came from a grocery store, and the entrees my husband & I had were very bland.