Are you planning a day at Animal Kingdom or Hollywood Studios? You might pick a place there.
ANIMAL KINGDOM
At Animal Kingdom, I like Donald's Safari Breakfast at Tusker House Restaurant. The food is outstanding and characters include Donald, Daisy, Mickey and Goofy all in their safari outfits. I'd go at 8am when it first opens. Having a reservation for breakfast gets you into Animal Kingdom Park before it usually opens at 9am. Then you are just a few steps from the Kilmanjaro Safari Ride.
If you're staying at a WDW resort, and you go to Animal Kingdom on a day when there are evening extra magic hours, the Tusker House Restaurant and Yak and Yeti Restaurant are open later and we love both. But it's a little harder for us to take time for a long table service lunch there because it takes time away from all there is to do. For lunch, a lot of people like Pizzasafari counter service - food is supposed to be quick and good (we are doing that next time).
HOLLYWOOD STUDIOS
At Hollywood Studios, I'd skip breakfast there and eat it on the go because Toy Story Mania fast passes go quickly. If you want to do that ride, I'd go to the park when it first opens (or extra magic morning hours is even better) to ride it and get fast passes. There are 2 fun places there for kids to eat - SciFi Diner and 50s Prime Time. I think it is easier to pull kids away from fun rides if the meal is also fun. Some people like Hollywood and Vine which has Little Einstein characters (June, Leo, JoJo, Goliath) but food doesn't get great reviews. If you want to do the Fantasmic Show at night, you might pick a fantasmic dinner/lunch package (book by phone only, not online) so you get preferred seating at Fantasmic and don't have to wait in line so long.