DTD: Wolfgang Puck's (the one by Rainforest) is the best CS in all of Disney IMHO.
Epcot: Sunshine Season's (The Land) & Tangerine Café (World Showcase next to Morocco). Our plan this year is to get a dish at one country, share it, and move on to another. We are thinking Tangerine, Japan, France, Mexico, oh and the School Bread at Norway.
MK: Cosmic Ray's (Tomorrowland): Chicken, Ribs, Green Beans & Mashed Potato platter on the free dinning plan is a beautiful thing. 2 people can split it. Something for everyone here too. Honorable mention for coolness; Pinocchios (Fantasyland) if you get a table overlooking the boats at Small World but SW is closed right now.
DHS: No favorites, do a table service at Sci Fi or 50's Prime Time for Lunch or take the boat to Epcot for a CS. If we have to, Pizza Planet for the Toy Story theme.
AK: Flametree (Discovery Island) but if its really hot and you need some AC, Pizzafari. The chicken sandwich was surprisingly ok there.