I would definitely rent a car, unless your going to be there longer than a week, and then it could get expensive. Even when we stay on Disney Property we rented a car. First, if you rent it ahead of time before you get there you can get a good deal. (We always use expedia.com) Second, we've always found for the cost of taking a shuttle from the airport to WDW and back it is almost as expensive as renting a car. If you want to go to Universal you have to take a taxi or a shuttle and it's at least $30. Also, it's nice to have a car to go to the grocery store, buy a styrofoam cooler and stock up on snacks and beer, soft drinks, and that also helps keep your eating costs down. NIce to have if you want to go out to dinner off of Disney property too.