What type of experience are you looking for? What is your budget?
If a regular sit down, I think Sanaa is a great OOP value and delicious food to boot.
Sci Fi lunch is fun (the food isn't amazing, but people go for the atmosphere) and not too expensive. We've paid for that OOP in the past.
Rose and Crown is affordable at Epcot and the food is good. When we went in 2009, there was a prix fixe. Les Chefs de France has a prix fixe lunch that a lot of people like (never done it). We loved La Hacienda de San Angel. It's a bit pricier than some of my other suggestions, but portions are huge. You won't need an appetizer or dessert.