L.S.
You don't neceasarily have to go completely organic in order to make an impact. I know that can be cost prohibitive for some people. What you can do is try and focus on certain foods that are better organic and buy others that aren't conventionally. We try and buy some organics -- especially milk and other dairy products. Another thing I've been trying to do is to not buy produce that was grown in, for example, Chile. Try and buy what's in season. That way food isn't trucked in and thus more expensive and using more gas and minimizing the footprint.
Almost forgot.... Coffee. We now buy organic (and free trade) coffee in bulk at either Sprouts on sale (it's the same price as conventional) or at Costco. It really isn't any more expensive.
http://lifehacker.com/software/food/five-best-foods-for-g...