Dave Hill has a smart review of the complimentary Disney Magical Express shuttle service. In addition to transportation from OIA to their resort, guests staying on Disney property can check in their luggage at their originating airport and not have to handle it again until it shows up in their room. Alas, this service is not for everyone and Dave does a good job pointing out some of the systems weaknesses.
Dave and his family make a yearly trek to Walt Disney World. You can read his 2006 trip report here.