okay - it depends on what you want. Do you want GOOD food or schtick?
Sci Fi is a "hmm - let's stop here" type of place, but not somewhere I'd prioritize.
My picks for really good food:
MK: nowhere, really - Cinderella's Royal table for breakfast, but not the world's greatest meal ever. Just pretty good. I like the stuffed french toast with the blueberries, but the rest is just okay. For counter service I'd say Pecos Bills, they have a good salad.
Epcot: Gosh, hard to pick here - lots of good choices. I'd say Le Cellier is my favorite sit down. The brats are really good at the Germany counter service, but I think my best method is just to stop at each country and get a little taste of something. We eat our way around the world (cannolis, crepes, dumplings, etc).
MGM my pick would be 50s Prime Time for lunch, for table service. Or Backlot Express for counter service (great veggie sandwich there). For dinner, Mama Melrose's.
Animal Kingdom - not much to pick from. I guess Rainforest Cafe, which isn't saying much

Maybe Tusker House or Flame Tree BBQ for lunch.
Resort/DTD "DO NOT MISS" meals for me:
California Grill
Chef Mickey's - breakfast (my "buffet" exception)
OHana breakfast
Kona Cafe Breakfast (don't miss the Kona Press Pot and Tonga Toast!)
Wolfgang Puck's
Wolfgang Puck's Express
Ghirardelli (dessert)