Nickelodeon actually has their own hotel in Orlando owned by Holiday Inn Resorts. I find Embassy suits to be the most family friendly because they have 2 conjoining rooms, a kitchen area and a sofa bed. They also give everyone in your family a full free breakfast in the morning! Great deal!
The Holiday Inn, Howard Johnsons, Motel 6, Hampton Inn, and Days Inn are all great hotels that offer wonderful deals for families traveling with kids and some even with pets!
There are a number of family friendly hotels in most states. Best Western hotels are family friendly. Also the Disney hotels are all family friendly.. Look for hotels where kids stay free and which offers a swimming pool as well as free breakfasts. A lot of hotels also offer day programs for kids.