I agree with the poster who said to avoid Chef Mickeys -- I was SO disappointed when I went there last month. Nastiest, dirtiest, ugliest buffeteria I've ever set eyes on (and $$$$$!)
The best restaurant experiences I've had on Disney property were at Le Cellier, Portobello, Fulton's Crab House, Hollywood Brown Derby, and Artist Point. What these have in common is that they are more "adult" dinner places with a somewhat quiet and relaxing atmosphere and you can really take time to savor your (delicious) dinner.