this is such a subjective question that IMHO there is no one "right" answer, it really depends on your personal likes and dislikes.
For the top tier I would put Le Cellier, The Mitsukoshi Tepanyaki, Marrakesh, San Angel, Coral Reef (although I think it's too pricey, you're paying for the view) chef's de France and Bistro De Paris. You can make an arguement for Alfredos and Nine Dragons, although I think both chinese and Italian foods are readily available all over America to the same or better quality at 60-70% of the price. I'm sure others will include some of those I've left out.
IF you're looking at Epcot, don't forget you have the option of using the International gateway exit to walk to the Boardwalk area and the other Epcot resorts. Restaurants in that area worthy of consideration would include Yachtsman's steakhouse, cape may cafe, Spoodle's, Flying Fish Cafe and in the Swan/Dolphin hotels you have Palios, Shula's steakhouse, Bluezoo and a coupel of others.