Rainbow Play Systems are the best quality swingsets and back yard play structures that we've found. They are solid, splinter free and hold up great through all sorts of weather.
Their prices are steep, but for this kind of quality it's worth paying more. They have a huge variety of designs that should fit anyone's needs, and will work with you on financing and payment options. Every system is expandable, so you can start small and add onto it as your kids grow. It's an investment that can last for many years to come.