Captain Cook's is my least favorite monorail CS location, although it does have dole whips which is nice.
Gasparilla at GF is my favorite. It has some upscale offerings, like lobster mac n' cheese, lobster cobb salad, shrimp stir fry, and more classic dishes like lasagna, burgers, salads, grilled chicken sandwiches, hot dogs, etc. Also, you can have a view of the castle while you eat.
Contempo Cafe is also up there. The offerings there seem quite fresh, like freshly tossed salads, sandwiches, burgers, flatbreads (I love the marinated beef flatbread with goat cheese, arugula, tomato, and caramelized onion), etc. Plus you can sit and watch the monorail pass by overhead.