It's too hard to pick just one!
Arthurs 27 in the Wyndham Palace near Downtown Disney is incredible. Pricy, but the view and the food are to die for.
The Peabody has Dux and Capriccio, which are both excellent. Dux is more upscale, Capriccio is still very elegant but slightly more casual.
The Renaissance has Atlantis, which served up one of the lovliest meals I've had in Orlando. Beautiful surroundings, exceptional service, fabulous food.
If you want something truly memorable in an atmosphere that will make your jaw drop, head over to Universal Studios and have dinner at Tschop Chop.
Grande Lakes resort has the outstanding Normans restaurant (everything is excellent!), Mall at Milennia has McCormick and Schmicks (fabulous seafood!).......there are so many places to get a truly exceptional meal in Orlando!
Enjoy!