We just ordered flooring samples for the house. We are probably going to go with bamboo because of its hardness, aesthetic and because it is an environmentally responsible choice. "Environmentally, it’s hard to argue with a wood-substitute that matures in three years, regenerates without need for replanting, and requires minimal fertilization or pesticides." Bamboo is also thought of as quite a luxurious surface by folks in India, because it provides a warmth missing in a place where many floors are marble or granite.
Another option for us is FSC-certified wood. This wood is more like the standard and exotic species more commonly used in the US. But the wood comes from trees harvested sustainably.
Finally, a third option is a hybrid approach. Weyerhauser has come up with a flooring system made from fast-growing eucalyptus trees. "Lyptus® Eucalyptus trees are grown on plantations certified to Brazil’s national sustainable forestry standard, CERFLOR. This standard has been mutually recognized by the Programme for the Endorsement of Forest Certification (PEFC), an international organization that endorses credible sustainable forestry programs." This looks like a promising alternative in a reasonable price range.