Park by park, my choices are--
Magic Kingdom
Pecos Bill's-- our favorite! Good burgers, great fixins' bar
Columbia Harbour House- nice change of pace from the burgers and fries
Epcot
Sunshine Seasons in The Land- a little fancier than normal fast food, but it's really good.
Kringla Bakeri Og Kafé- Norway- great pastries! A good place for a snack.
Disney-MGM
ummm......I'm thinking....really, I am....

this is by far the worst park for food in general and CS in particular. The Backlot Express isn't bad for basic burgers and fries, or we'll just grab a turkey leg from Toluca Legs on Sunset Blvd.
Animal Kingdom- the best CS at WDW
Flame Tree BBQ- great ribs, and nice peaceful seating areas overlooking Everest. Our favorite.
Tusker House- atypical fast food. The 1/2 chicken is great.