Does a family really NEED a 2500 sq ft. house? I've found that living in California where houses are expensive has resulted in a space thriftiness that has kept me from buying too many physical goods which will eventually end up in the landfill. In many ways, abundant space promotes a culture of cheap, disposable products rather than fine, durable, space-efficient goods. Here's an amazing video that demonstrates how wonderfully efficient and beautiful well-designed furniture can be:
http://www.youtube.com/watch?v=GRxvNhlS4V4