Remodelling, is very difficult to do in a "green" way, though we did the best we could. We reused two mirrors in the new bathroom. We recycled every bit of cardboard, plastic and metal we could. It's truly amazing how much cardboard there was from the packing for the new elements. I purchased low-VOC paint from Home Depot that I was very pleased with, and thankful not to have that intense paint smell in the house during a week when we had to keep the house closed up tight.
Still, a lot of stuff went to the landfill: old ceramic flooring with it's cement sub-floor, some rotted wood sub-flooring (so glad we found that and could get it repaired!), wall tile and sheet rock, and the dilapidated cabinet. A lot of heat energy was lost from the house on those cold days as the remodellers ran in and out to their truck and to the back yard, where they were sawing things.
There are a lot of things I love about the "new" bathroom, but I think my favorite is the Solatube skylight. All day long the bathroom is bathed in warm light, even on the cloudiest days, and it is unnecessary to turn on a light in there at all if the sun is up.
I also am kind of amazed by the new water-saver toilet. We had one from the first generation of water-savers and it... didn't really do the job, if you know what I mean. This one is tremendously better. I did a little rough calculating and I think it should pay for itself in reduced water bills within about 15 months. Toilets are relatively inexpensive. If you can possibly do it, I would encourage you to think about replacing your current one with one of the new ones, for both financial and environmental reasons.
I learned another interesting thing during this process. It is not recommended that a Formica-type laminate counter top be used in a bathroom any more. The glues used to make them have been reformulated to make them safer, and they don't stand up to the warm, steamy environment of a bathroom. That meant I had to look at solid surface counters. I had some crazy luck- there was a pre-drilled granite counter top that was on sale so cheap (and included the sinks) that it cost less than other more plebeian choices. This was a sort of embarrassment of riches!
In the end, we wound up with this:
Our daughter, currently the main user of this bathroom, says it looks like it belongs in someone else's house, because it's "so trendy". Of course, ten years from now it will be passe and outdated, but we're not exactly slaves to fashion, so this is probably how it will look until Mike and I can't live in a house with stairs anymore. Fortunately, I'm pretty happy with it.