you should book the room right away to make sure that you get a room. Once any special offers come out you can modify your reservation. As to when specials for that time frame are normally announced, I don;t now.
I disagree. I'd wait until October when it's likely that any discounts for that time period will be announced. I never book a trip at full price because I know I'm not ever going to pay that amount. I just wait until a discount is offered that works.
I like to book right away through Disney to guarantee the room. You can cancel and modify without fees right on up to like a week or two beforehand I think. 3 to 4 months out is a good time to find the deals.
I just cancelled my main Disney reservation and rebooked using ebates to cheaptickets because it saved me $70 on our stay at a suite at AoA in December. Disney had no problem with the cancellation and my deposit will be back on my card in 7 to 10 business days. Which is good because I had to pay the whole thing up front for cheaptickets (but I'm all about the savings!)
You can modify your reservation if any deals come out, so there's no reason not to book it as soon as you have the $200 deposit. If Free dining or any other promotion is announced for your dates, you just call and have it applied!
We book as soon as we know what resort we want and our dates are firm. If a discount comes out and your reservation qualifies for it, you can add it later.