Orlando
Unless you are staying within the Disney complex and you are not going to venture out... you need a car to get about.... and the beauty of having a car means that you then don't have to be tied to the Disney complex... and if you are not tied to the complex you have a broader scope of accommodation available to you. A good base for exploring, not just Orlando but around, is Kissimmee - there are also some "lesser" attractions in and around Kissimmee, such as Gatorland Zoo.
Orlando is a great initial base and if you are not wishing to merely spend all of your time trudging around large theme parks it is worth exploring Florida in more detail and a chance to go to the Everglades National Park should not be missed. Of course, one of the most wonderful things about Orlando is just how child friendly it is - this is probably one of the easiest places for a family to holiday!


The back of Disney's Wilderness Lodge
My 2009 Disney photo album
Universal Studios
Apollo/Saturn V Center