We were able to negotiate a slightly-better-than-originally-quoted rate for our stay in a Windsor Hills townhome during MLK week later this month. Original rate was to be $800 for 8 nights, but we are paying just $760.

This is a flat rate which includes pool heat, taxes, etc... which I think is a truly excellent deal!
As far as the original quotes we received, we found that once we added pool heat and tax to many of these, they were nearly double the amount above! DOUBLE! Can you believe that? For the exact same structure with the exact same splash pool! We are VERY budget-minded and don't feel it necessary to pay hundereds of extra dollars for the owners' specialty paint, designer couches, or plasma TVs. We spend most of our time in the parks anyway and think of what we could do with an extra $700!
Anyway, we picked our 3 favorites (which happened to be the 3 that were offering the lowest total cost combined with our 1 must: a high chair) and I took the advice that I read here on the DIS! I emailed them and explained our siuation and asked if the price was at all flexible. It worked!
By the way, we booked right at 2 months out and I do think things are more negotiable the closer you are to your trip dates.