Have you thought about cork? It is something that I am considering when I update my kitchen. It comes in a variety of colors and is easy on the feet.

Lisa Goldstein-Savelson,

Cork flooring offers a comfortable, resilient feel underfoot in the kitchen. It provides acoustic and thermal insulation ("warm on the feet"). It also comes in a darker color ( http://www.novafloorings.com/products.htm). The real kicker is that it is a renewable wood source in that:

"Trees must be 25 years old before the first harvesting (virgin cork) of cork can occur. Average life span of the cork oak tree is 150-200 years. The older the tree is the better quality of cork it can produce. Every 9 to 10 years, the bark of the cork tree is stripped from its trunks."

Here's a couple pictures of a recent kitchen remodel in which we installed cork flooring. Best of luck!

Have you thought of poured resin floors? Not sure how well known these are in the US, but they are quite popular in the UK and Europe... http://www.solidfloor.co.uk/seamless/Something to add to your list of considerations....