I stole this from Molly's blog. It's long, but good, so make sure you have time to read it. The comments are also insightful. Like this link that one posted; driving 55 mph on 35 might get me honked at, but it's something to consider.
Really, every time I read or hear about some great effort of change, I feel lazy, responsible, guilty, so so sad. But I try to make some small changes; step by step I'm trying to be a better citizen (one commenter on the article notes we are no longer referred to as "citizens" but instead as "consumers"). After I read Kingsolver's Animal, Vegetable, Miracle last year, I wanted to do everything possible to buy only local and organic. That lasted about a week. The only thing I regularly buy organic now is milk, and even that is because it tastes better. On this website, they say though, that even if everyone ate only one meal a week consisting of all local foods, it would make a tremendous difference. Baby steps.
Oh, and this, found also on Molly's blog (she is an excellent finder of cool things), will leave you open-mouthed with wonder, but thoroughly amused and educated (sound required, so don't watch it at work).