Kimberly:
If your children are picky eaters, Restaurantosaurus with its hamburgers, hot dogs and chicken nuggets typically will fit the bill. However, I always find the area crowded.
Yak and Yeti's counter service is for a more adventurous eater, offering dinner bowls with LOTS of rice and the entree served on top. I always feel like I'm not getting the best value out of my serving sizes there, though. However, if you want to only spend a snack credit for the kids, the last time I was there, you could get an eggroll as a snack.
Flame Tree BBQ makes a good compromise between familiar and far out. Two reasons it tends to be my top recommendation at Animal Kingdom: large portion sizes that can be shared and their calm patio behind the restaurant near the lake. Compared to the other two locations, it makes for a welcomed respite.
Disney's Hollywood Studios is another park I tend to opt for counter service. Pizza Planet's pizza crusts leave something to be desired and are not even as good as what you'd find in the frozen food section of your super market, so unless you have picky eaters, it would not be my first choice. If your kids like Mac 'n' Cheese, check out
Fairfax Fare. The weather will be nice to enjoy the outside seating, too. Chicken nuggets will be on most of the kids menus at the counter service locations at DHS with a delicious grilled vegetable sandwich on the kids menu at Backlot Express or a cheeseburger at ABC Commissary. My favorite dining location is Studio Catering: lots of seating and in December the weather should be mild enough to enjoy it.
Wishing y'all a magical vacation!
Whitney