With kids 3, 5, and 7....you can't go wrong with character dining. Our favorite character dinner based on the quality of the food is 1900 Park Fare. However, this is a buffet, which might be a lot of work with 3 kids. Character meals that are not buffets are available at the Liberty Tree Tavern and Garden Grill. Chef Mickey's is a great buffet and very lively atmosphere--we love it, but I think the food is better at 1900.
As to my favorite 1 TS restaurant....probably a toss up between Le Cellier and Les CHefs de France. They are both appropriate for the family, but the kids would probably enjoy the characters more.