I've got passes and have done all CS over the past year. Only reacently have I started doing TS. So I will give you my tips on CS.
Pecos Bill at MK is nice if you are really hungry and like veggies. They have a taco salad which just comes with the shell and meat. You add in the toppings yourself. This is a great item to share because you fill it up yourself.
Colombia Harbour House is my favorite CS in the parks (it's at MK). The macaroni is filling for the kids. The food is decent for a CS. But the best part is going upstairs to eat. Even on busy days, it's fairly deserted upstairs. It's a great place to have a "time out" and unwind.
At Animal Kingdom, Flame Tree BBQ is nice for a CS but it's outside. So you will have to judge on how hot the day is.
At Downtown Disney, Earl of Sandwich is awesome for CS. The subs are only $6 and super yummy and filling. The place is always super busy though. But the line actually moves very fast.
In case you don't know, you can bring food into the parks.
Beyond this, we spend most of our times just snacking in the parks and not eating an actual meal. Most snacks are around $5 and Disney has some really yummy ones. Cupcakes are H-U-G-E. My 5 year old and I can only finish hald of one together. They are the best cupcakes I've ever had. Specifically the choc/peanut butter and red velvet cheesecake at Starring Rolls at DHS, and the Cotton Top Tamrin from Kusafiri in Animal Kingdom.
The egg rolls, turkey legs are very good. Yak n Yeti has fried rice for $4 (in animal kingdon). Stuffed pretzels are nice. Caseys corner has yummy corn dog nuggets with plastic cheese.
And all bakeries are your friend! They usually have huge sandwiches for around $6 and all the pastries are good.
Ice water from the vendors is free.
If you can afford it, and it's pricey, prepay for the Wishes Dessert Party. It's a dessert buffet with just desserts. They are okay, nothing great...but who doesn't love dessert? But it's very magical to be able to sit and watch the fireworks without people elbowing you. Plus, Tinkerbell flies right over your head. It's a pricey thing and wouldn't repeat it, but it's worth doing just once.
Get first visit pins for free from guest services.