You may have been sent this video by a green-minded friend already and if you've never taken the time to watch it, do now. 

www.storyofstuff.com

Annie Leonard walks us through the life cycle of the stuff we consume.  From extraction to production, consumption and disposal, she illustrates the big picture of consumerism and the problems built into the system. 

In my opinion, the most important part of this video is the explanation of 'externalizing profits' as Annie puts it.  This is what allows us to buy our goods for so cheap and its destroying habitats, communities and lives all along the way and its a major problem with the way the system works today.