The Crystal Palace at the Magic Kingdom has breakfast, lunch & dinner character meals. The food here is excellent and so is the service. Another character breakfast option is Goofy's at the Beach Club. I hear that one is good. Chef Mickey's is good for breakfast, but I would stay away from it for dinner (yuk). There is also a character breakfast at O'Hana's at the Polynesian (Minnie I think), as well as breakfast & dinner at the 1900 Park Fare at the Floridian (Cinderella).
Oh, just remembered that they have a princess breakfast at EPCOT now, so this may be a great place to start your vacation!