These are available in recycled rubber and polymers that similar to slate. These are lower maintenance and lighter than conventional roofing.
Counters and Showers
Using glass and concrete mixed together gives your counter top or shower surround or even floors a beautiful but durable finish. Concrete is of course a fairly heavy material so make sure its well supported.
Avoid old growth and scarce tropical hardwoods. Look for wood from managed forests (think: Forest Stewardship Council seal). Also try reclaimed wood from old buildings or riverbeds. Composites are also worthwhile if they are formaldehyde free. Composites are basically made from sawdust and glue.
Cellulose insulation is made from plant fibers or recycled newspaper. It can easily be blown in tight spaces and insulates better than fiberglass (higher R value). Cellulose does not itch like fiberglass although caution should be taken because of the dust it can create. A simple HEPA mask will cure that issue though. Check out Green Fiber for a sampling of products and to look for dealers.
Flooring and Carpetting
True linoleum is a fantastic option since its made from linseed oil, pine rosins, and wood flour on jute. Beware though, as some people refer to other flooring as linoleum when it is in fact made from polyvinyl chloride (PVC) which has a toxic side to it. Also try to use wool or sisal carpeting. Choose a 100% recycled fiber carpet or some carpets are made from corn/plant based plastics.
Structural Insulated Panels (sips)
These are two sheets of OSB or plywood with foam board sandwiched in between. Since these panels can come up to 24 feet wide, there is less heat loss due to air leaks.
Switching to a low flush model can save significant water in a year. New models are required to use 1.6 or less gallons of water per flush. Some more environmentally friendly models have a hand sink built in the top so the water you wash your hands with will flush your toilet next time.
Tankless Water Heaters
Tankless or on demand water heaters work by running the water through a series of pipes that lie parallel to or wrapped around a heating element. This in turns directly and rapidly heats the water for your use. More energy is used for a shorter time to heat the water. Overall, less is used since its heating only the water you're currently using rather than maintaining a constant temperature on water you may not use for a while. These are available in gas and electric versions.
Try to meet standards when building or renovating. LEED is becoming more common throughout the United States. Its largely focused on energy efficiency though. Passive House takes energy efficiency to the extreme with the use of SIPs to minimized heat loss, properly placed windows for passive solar heating, and heat exchanging ventilators to keep the air fresh without losing heat in the process.