Terrazzo floors. Seemingly indestructable, terrazzo gets an A+ for durability, and also for its good looks. This material, made of chips of marble or granite set in concrete and polished, can score high for sustainability too if no- or low-VOC sealers and low-impact aggregates (like recycled glass) are used. Terrazzo's one shortcoming is that it can be tough to stand on for long periods of time.