What parks will you be visiting at Disney? there are some not-too-shabby choices that aren't overly expensive compared to most of the food that is down there.
You can get a great idea of their food at allearsnet.com which is "deb's webpage" known to the locals.
Orlando does have a lot of chains but you may also check out mycityeats.com to see if there is anything that looks good in the area you'll be staying near.
I know that toward the airport and not so much toward disney there's a Cracker Barrel and a Joe's Crab Shack which are both pretty good.
In the parks themselves if you'd like to stay on the cheap (which who could blame you when a sit down lunch cost more than a nice dinner sometimes) I recommend the Columbia Harbor house in the Magic Kingdom. They have some fish and chips and a cool upstairs where you can watch the people walk by while you eat if you find the little nook I always like to sit in. There is also an affordable noodle type place down mainstreet and to the right before you get to future world.
In Epcot there are lots of dine in restaurants but also cheaper but still delicious eateries that are usually found outside. Mexico has a nice one, China, Japan, Germany, and Morocco too. Stuff ranging from big taco salads, orange chicken, brats and saurkrat (and beer!), to Gyros (aka lamb wraps). All depends on what you like but these meals tend to be in the $10 range instead of the $25-30 range a lot of dine ins can be. Oh, also in Epcot, there's a fantastic pastry shop in France you can't miss either but its up in the backside of the country so you may have to look for it a little bit.
If you visit MGM, while it is a tad expensive, the Drive-In theater is a must-see if you have nolstagia about old drive in theaters and sci fi B movies. There are a few quick eateries there but they don't come to mind off the top of my head.
Animal kingdom has a great barbeque place! There's also an asian restaurant that is a little pricey but we'll go and share an appetizer dish that has dumplings and stuff and it isn't too bad doing it that way. They have little stations for tea and specialty items too to keep you cool in the heat.
I don't know if you're staying just near disney or on it but another relatively inexpensive way to eat is to visit the disney hotels. They are a sight to see themselves and many have a food court or counter service that won't put a big hole in your pocket. My favorite is Port Orleans Riverside- they have a great food court by a big water wheel next to an old swimmin hole. When you're with family who can beat having a variety of food options?
Now I'm just getting hungry thinking about this
Downstairs in the Polynesian hotel is a cool eatery that has burgers and what not. There's a nice restaurant that is very florida themed and not too bad called Olivia's I believe at the key west resort too.
There are restaurants at Downtown Disney like the Rain Forest Cafe and other themed ones but may be a tad pricey for what they offer.
Hope this helps a little bit <-- huge disney fan
