Hi Amanda, and welcome to the DVC! We love our membership and I'm sure you will too. The first time we walked into a resort and the cast member said, "Welcome home" I got tears in my eyes!
Have you weighed the pros and cons of the dining plan? It always works out in our favor and my family loves to take advantage of that offering. No matter how you're dining, be sure to make your reservations well in advance (up to 180 days) as many meals do fill up.
I'd recommend looking at the park hours, which are usually posted 6 months in advance. From that I make an itinerary of where we will be each day, then decide where we will be eating accordingly. You can find the hours posted
here. Don't forget to research Extra Magic Hours (EMH)! Now that you will be staying on-property they are a great way to visit the parks in less-crowded times.
I'm not sure exactly when in September you are visiting, but if it's later in the month you might be able to catch Mickey's Not So Scary Halloween Party in the Magic Kingdom one night. It's tremendous fun for the whole family, and we love to attend. Dates for 2008 have not yet been announced, but you can check
this page for updates in the future. I recommend buying tickets in advance, as many nights do sell out.
Enjoy your first trip home! :)