I am not sure what you consider a big town. But I don't believe any of are areas are big. What price range are you wanting to stay within? This determines a lot.
How old are your children? You may want to begin your search by researching schools. Try
www.greatschools.net.
I agree with the above poster about Mount Pleasant and Summerville for a great family area. Mount Pleasant is closer to the beach and downtown..more expensive. Summerville is less expensive but further from beach and historic Charleston.