Where is a great place in florida for an 18th birthday?

every year the place we go gets better for birthdays. for 15th we went to disney, for 16th we went to busch gardens and seaworld, for 17th we went to St. Augustine. Now I'm not too sure where we should go that would be fun, but we are going to do it in december December, so all the sunny spots wont be as welcoming (did i mention we want to stay within Florida?? lol)