Lemnia,
I'd just echo what others have said.
My two kids (now 16 and 11) really like Ambergris Caye. They especially like San Pedro -- being able to walk safely around town, exploring a bit. The water and beach activities are great of course, though my kids get the most enjoyment out of a hotel pool. Not all the hotels and condotels on the island have a pool, but it's a must for us. Most of the mid-range and up places also have cable TV, which, I have to admit, is an attraction for my children.
All the restaurants on the island are kid-friendly, even the most expensive ones such as Mambo, Capricorn and Rendevouz (although if your kids are like mine they'd rather eat pizza or seafood or a burger at a place like Fido's or one of the less expensive casual restaurants.)
--Lan Sluder
Belize First Magazine
http://www.turq.com/belizefirst/