The boat trip to the Yangtze delta is a great Shanghai excursion. The delta itself is not very interesting, as there's water everywhere and you can't decide whether you're on a river or the sea. But you pass the old harbor of Shanghai and you can watch all the locals working in the dockyards or on their houseboats.
Another highlight is, of course, the impressive architecture of the new city-centre Pudong. When you do the trip in the afternoon, you'll be back just before sunset and you can shoot great pictures.