Community Forklift in Edmonston, MD sometimes has lightly used floor coverings. It's a good way to keep materials like carpet out of landfills and put it to good use.

Similarly, Habitat for Humanity runs ReStore in Alexandria, VA.

Bamboo is considered one of the best choices as a sustainable environmental product for hardwood floors. It is available in either a distinctive style where you see the "knots" that occur in bamboo every six inches or so, or a conventional grain look, where the bamboo is cut so you don't see these knots.

You can choose from a variety of colors: ranging from a light "natural" color to a darker "carbonized" finish. Don't worry, once it's dried, bamboo isn't green colored like you think of live bamboo.

"Carbonized" bamboo flooring in amber shade

Bamboo grows fast, so it's a great choice versus other woods. To give you an idea, bamboo matures in 3.5 to 7 years, vs. 120 years for oak. It can be cut and will grow back quickly and is considered a "sustainable" product.

Bamboo floor manufacturers and online retailers:

Bamboo Flooring International Corp.

Bamtex

iFLOOR.com

TimberGrass

Palm is also gaining popularity. Once palm trees stop producing coconuts, they are cut and new ones planted.

Durapalm

A good article about Flooring for the Environment