I'm not an eco warrior but I have made a tiny difference
Back in March http://mckinleyresource.wordpress.com/2009/03/31/so-how-green-can-i-be/) I waved goodbye to my lease car and took the decision not to replace it. As I said then, not an easy decision i've had a car since I was 17 and have got used to stepping from the front door in the morning and stepping straight into my car. So as a quick update, it's been tough, sometimes tougher than others but I've stuck with it.
Now as I said i'm not an eco-warrior and in the last 3 months I have hired a car 6 times but because I've booked a hire car I have saved up my journeys so to speak making sure I see as many people as I can in the time I have the car. But 6 days out of 100 odd seems a good thing to me, it means those short hops to the office have been eliminated, I walk an awful lot more. In fact I walk miles. This is hopefully better for me and certainly better for the environment.
I think I am more aware of my community, I see people and because they now see me all the time they say hello, I like this.
I have also found that I am more planned. If I am using public transport to get somewhere I allow a lot more time than I would have done normally with the result that I get to places early (those of you that know me, know that I am the king of cutting it fine!). This new found travelling time also means I read more and listen to more music or rather less radio which is actually a good thing I've found.
So for now, i'm sticking with it until I wear out more shoes (killed 1 pair of converse so far) or get caught in a downpour again because I forgot my umbrella, luckily on the way back from a client so they missed the drowned rat look or until I really can't carry any more stuff from the supermarket.
You should try it, not in a moralistic i'm better than you way but just miss out a journey in the car or two and see how it goes, you'll feel more connected to where you live in some way... honest.