I'm not too sure what you're budget is, however, these are my recommendations:
Magic Kingdom
--Cosmic Ray's in TomorrowLand is good. They have a little bit of everything and the atmosphere is interesting.
--Crystal Palace off Main Street is great for kids. Lots of character interaction and very good buffet style food.
--Mrs. Potts in FantasyLand has great ice cream and ice cream sodas!!
--In FrontierLand, they have awesome turkey legs and churros to munch on from a street vendor during the parade.
EPCOT
--Garden Grill in The Land.
--San Angel in Mexico. It has awesome atmosphere and great food.
--Biergarten in Germany. Great music and entertainment.
--Le Cellier in Canada. Good steaks, but pricey.
Animal Kingdom
--Tusker House in Africa. Great chicken.
--Pizzafari on Discovery Island. Great brick oven pizzas.
--Rainforest Cafe at entrance. If you have never been to Rainforest Cafe, it is a must see. Awesome atmosphere, however it can be a sensory overload and overwhelming at times. There is also one in Downtown Disney.
Disney Hollywood Studios
--'50's Prime Time Cafe. 1950's style atmosphere with a "different" style of service...almost like you're at home.
--Brown Derby. Nice atmosphere and moderately priced.
--Mama Melrose's. Great Italian food!! One of my favorites.
--Sci-Fi Dine In Theater. A very unique experience where you dine in a car and watch old cheesy science fiction film clips while you eat. It's good to do once, but I personally won't do it again. The food is just okay.
--Toy Story Pizza Planet. Great brick oven style pizzas with a Toy Story atmosphere.
These are just some of my suggestions for the parks. There are literally hundreds of places all around WDW, such as the resorts, Downtown Disney, Disney Boardwalk and tons of other restaurants throughout the parks that you could eat at. Your options are truly endless.