An Illuminations cruise is always a good special treat, particularly if you don't visit the parks everyday, it's a way of getting a great view of Illuminations, without having to use a themepark ticket for Epcot.
If you like getting out to see the local wildlife we took a trip around the Disney Wilderness preserve that is out in Poinciana. It's about 20-25 miles south of WDW and takes about 30-40 minutes in the car. We went out for their tour on a "swamp buggy" ( bit like a bus sized quadbike ) we were out for about 2 hours. There are also walking trails. We saw deer, aligators, a coyote and LOADS of birds. We also saw tracks of bobcats,foxes, feral pigs, tortoises and armadillo.
http://nature.org/wherewework/northamerica/states/florida/preserves/art5523.html
If you like art the Dali gallery at St Pete's is definately worth a trip, you could make a full day(or even two) by visiting the sunken gardens in St Pete's as well. Here's some information on both
http://www.stpetersburg.com/attractions/index.shtml
An unusual day out would be the Historic Bok Sanctuary in Lake Wales ( about an hour's drive from WDW)
http://www.boktower.org/ . I thought this looked a really cool place to visit sometime.
If you fly into/out of Miami or wanted a short trip down there the South Beach is full of history and the Art Deco buildings are just everywhere. There are some great boutique hotels to stay in as well. While in Miami you could visit the Vizcaya museum and gardens
http://www.vizcayamuseum.org/ or spend a day at the Venitian Pools in Coral Gables just south of Miami
http://www.venetianpool.com/ . Definately a different type of waterpark LOL
P.S. for anyone interested in the historical homes, gardens and building I got a great book recently that lists quite a few of them. Anyone who wants to see more examples like the last few I've put up I have information on similar things dotted alll over Florida.