If you are building and you can afford the hardwood, I would do it now. It is a generally more durable condition than carpet and especially if you have animals or allergies, it will be easier to keep clean. You can always put in area rugs if you want them. They are easy to change later if need be.

If your children are very young (toddlers) I would carpet their bedrooms and think about hardwoods when they are a bit older. Hard surfaces are tough on small fry learning to walk. I remember when ceramic tile floors for kitchens were hot, and several young children had injuries from falls on the hard surface when they were still uncertain on their feet. From then on I encouraged parents to consider vinyl for those first few years.

We have solid oak floors in the main area, basically everything but bedroom. Our baby has grown up with that...the hardwood is still pretty resilient and bouncy. We just avoided socks to keep the slip factor down.

We have carpet in the bedrooms. It was cheaper, so we did it that way. If I'd had the money I'd have done cork or continued the hardwood.

Def. hardwood if it fits into your budget. Or...best of both worlds. have you seen www.flor.com ?