One of the things that makes it difficult for most people to radically change their ecological footprint is that the big differences come from, well, radical changes...
I'm not going to put myself up on a pedestal here, but we chose where we wanted to live by planning out public transportation and biking distances first, then setting a budget, then house hunting. Which means we live where we can both use public transportation OR bike to work, because we set that as a condition before moving. It's a lot harder to change the public bus route (or change jobs) after you've moved
Ditto for various activities, we chose a place to live that has a reasonable amount of sports activities available for our son nearby, because we refuse to drive him around more than necessary. Most of this we did to buy us more time and less everyday stress, but it sure cuts way down on our car use.
Come to think of it - we didn't HAVE a car when we moved here. Hm, maybe that had something to do with it... 
Now, if only I could get away from the idea that I truly deserve a trip to Thailand next winter.
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett