If you are planning on dining in the parks rather than the resorts...
MK I loved CRT for lunch, we had a table by a window and enjoyed a lovely MK view, the food was nicely presented, and while not a four star restaurant or anything, the service was good, food decent, atmosphere...great (and the youngest of us is DD 17)
MGM Brown derby is fantastic. I agree with everyone else.
AK I only tried Rainforest Cafe there......the service was good, food so-so.
Epcot: So many choices. The Morroccan restaurant...the sit down one is beautiful and features a belly dancer...
I would say that unlike many others my experience at Tony's Town Square was pretty awful. The server was the rudest man I've ever encountered anywhere... and he gave poor service... he never refilled drinks, would not bring parmesan cheese for my pasta...his demeanor actually changed when I told him we were on the Premium Plan, I guess he figured his tip was included so he didn't bother to be either attentive or polite...it was the only place during the week that I did not leave additional money for the server (above the included 15%)...and the food was not very good. Maybe had we not been on the premium Plan our experience would have been different. But it was the worst experience of our trip...it is now the family joke, the benchmark of bad...