I'd have to agree with the general concensis that if you love going to Disney, DVC is a great bet, but the trading aspect of ownership may leave you with a bad taste in your mouth.
My own experience has been one of mild displeasure. I traded 160 developer points into RCI and had to be very flexible about the resort and time of my vacation just to use the points. I ended up with a place that was still under construction (with NO pool, clubhouse or anything else) and having to find out that information on my own.

(I decided to go through with it anyway because we wanted the area, not the resort amenities, but that is besides the point.)
Recently, in planning 2010 vacation, I looked at the RCI selections, and was dissapointed. There aren't many locations available in places I want to go (Mid Atlantic, South (but not Florida)) and the reorts didn't seem to be anything special. The pictures of some looked like the resorts were decorated in the 80's, not exactly what I wanted considering the quality you can get at our resorts at Disney.
If you want to just trade a timeshare and vacation in different places every year the resale market is full of much cheaper alternatives than DVC. The Magic of Disney however, is something that you can't get anywhere else. Maybe buying a smaller contract with DVC that you can use every couple of years is a better deal, and buy a regular timeshare to trade off with as Littlestar suggested.
