Do what I usually do my last night at WDW: stroll down Main Street towards the train station, sit on a bench just outside Tony's, people watch and take in that unique atmosphere...
I'd ride the monrail around the lagoon a few times, then get off at the magic kingdom and walk around. I dont' even know if i'd go any attractions, i'd just want to enjoy the last hour.
One last walk down Main Street and through Cinderella's castle, then pose for a pic with the Partners, and then what I usually do... POWERSHOP for all the people that I could have shopped for on my first 5 days there!
Boardwalk to SpaceShip Earth, buy some pins, and back again, all in 40 minutes... WOO HOO