I like Capitan Cook's at the Polynesian. They have very good "gourmet" pizzas that I believe were just added to the menu last year. Along with the typical sandwiches and burgers, they also offer sushi (very surprising) and some more exotic salads. Also, a selling point is the Dole Whip machine which is hard to pass up. The whole menu seems to lean toward the pan-Asian cuisine keeping with the resort's theme. For breakfast, they also serve their famous Tonga Toast a-la-carte if you choose to go over earlier.
I've never been, but I will try out Roaring Forks @ the Wilderness Lodge next week and post back when we return. From what I read, it sounds as if it has more "American" style offerings.
I'm afraid I don't have any personal experience with Contemporary or Grand Floridian counter service dining. I guess I will need to book two more vacations soon .
Even though it is "in park" dining and very simple fare, Casey's Corner has become a tradition with my clan. On a whim, we ducked in to grab a quick bite on our '06 trip and it became my wife's favorite MK restaurant.