a certain shade of 'green'...
Apparently, in the long run (or walk, as it were) walking 1.5 miles to the store and back can be more detrimental to the environment than driving. How? Well, you'll have to read yesterday's Freakonomics blog entry to see.
A related, slightly older post from the same source - apparently cutting water consumption isn't all it's cracked up to be.
I highly recommend this blog (and the book it followed). In fact, the Freak blog is a shining example of using the medium to, as the PR gurus say, 'continue the conversation'. How so? Well, Freakonomics the book was released back in 2005, and with this blog the authors (and some notable guests) have managed to maintain a connection to their audience. (It probably helps that they contribute to the New York Times regularly as well.)