I bought into
Boardwalk and
Old Key West - both during 2009. Just 50 points each so not a lot. I was tempted to buy my first contract straight from Disney while I was on the Disney Magic, but I'm glad I waited until I got home so I could do my research. I bought both contracts through resale - it allowed me to buy less points (for less money!)
So far, I have stayed at Kidani Village (studio), Grand Californian (regular hotel room... before the villas opened), and Beach Club Villas (studio). I ironically haven't had the chance to stay in either of the resorts I bought into, but hope to soon.
I don't think I have a favorite resort yet... I want to try them all. But I must say that the slide at Kidani Villiage is awesome!!! I hope to make it back to BCV when it's not so cold so I can try out their lazy river/pools and slide.