I can heartily recommend
www.villadirect.com and specifically the Sunshine Bay Villa in Oak Island Cove, which is right across from Windsor Palms. It's a beautiful, newer home, 4 bedroom, 3 bath, beautiful pool overlooing a wetland area where you can see cranes, etc. Nintendo for the kids, themed bedrooms for them, gorgeous masters (2) for adults, garden tub in one, spa, big screen TV, and beautifully decorated without being stuffy. It has an alarm too, on both the main house, plus a pool alarm if you want to keep the little ones from the pool area.
We loved it there and have stayed there a couple times, and will again this summer for the second part of our trip.
The best part? It's priced from $130/night, depending on the season.
Villa Direct is great to work with too. They have tons of homes if the Sunshine Bay Villa isn't available.
Highly recommended!