It really depends on when you are going. Marathon weekend from what I understand can fill up pretty quickly. I am itching to book my reservation, but have to wait until the points (DVC) are released for 2008 WDW resorts. We want the Polynesian King Kamehameha Club!
On the other hadn I will be booking starting Sunday for the BCV!! YAY!! We will be there from 1/16 -1/27.
I booked already, but part of my time was for New Year's Eve. If you book a package you only have to put a $200.00 deposit down, room only is 1 nights stay. I would book now, you can change it later. I have changed my resort a couple of times. The marathon starts Jan.11 I believe. I think it gets pretty packed for that.