I think this is a brilliant idea! And it relates to positive environmental karma in the following way: If we are to see our existing possessions and appreciate them, hopefully that will help calm the beast of consumerism in us. When we appreciate what we have, surely we will have a lessened need for more new stuff.
There are some eco-decorating ideas in this Martha Stewart post. I particularly like the arranged bottles idea (photo at the top). Cost: $0. It's beautiful and great reuse of stuff! (On a side note, I used to make fun of Martha Stewart, but I really like her magazine these days. My library carries it! Wahoo! I see in her magazine a strong alignment toward positive environmentalism. For example, when talking about plants, she recommends nontoxic fertilizers and natural pest deterrents.)
Quoting Sheryl Crow's song Soak Up the Sun (she may be quoting someone else, I'm not sure): "It's not getting what you want, it's wanting what you've got." Makes sense to me!