Wouldn't lino be the most eco friendly and easiest to maintain? I'm thinking of a manufacturer such as Marmoluem, which makes tons of colors and patterns. I prefer lino in sheet form, not tile as there are less problems down the road with tiles getting moisture underneath or corners aging badly. The other stones are all gorgeous, much more expensive, hard on your feet (and anything you drop), need to be sealed occasionally and need to be jack hammered out of the earth, then transported great distances, then fabricated into tiles or slabs, then installed. Phew! But they're a much different look than lino.