The WS in EPCOT has a number of nice places to have a dinner or lunch (or even breakfast now). If you want to dine within the park, you may want to consider, Le Cellier, or Marrakesh, or France (two full service, one Le Chefs, the other the Bistro) or well...any of the countries that appeal to you!
There are many nice restaurants between EPCOT and MGM Studios too. The boardwalk has a few, Flying Fish, Spoodle's, Big River Grille (not my favorite) as well as ESPN (NOISY!!!!!). There are the resort restaurants as well. Cape May in the Beach Club. Yachtsman Steakhouse in the Yacht Club. There is the Y's Galley too, but I can't recommend there.
The Swan and The Dolphin have the market cornered on a variety of full service restaurants.
You won't have much trouble finding some where to eat!