The warm look and feel of hardwood comes in such a bewildering variety that even traditional options like oak, chestnut, and pine come in categories like wide plank, wormy, and rustic recycled. Add eco-friendly bamboo, sumptuous exotic mahoganies from South America, and Asian teaks and walnuts, and the floor shopper may long for the days when choosing a shade of stain was the hardest decision to make.