I have already said that I find trips to the grocery store crippling: last time I went I stood in front of the organics section of shampoos looking at ingredients and labels trying to figure out which ones were biodegradabale, not tested on animals, hadn't used any pesticides in production, might also be local, and didn't cost a mint. At least 15 minutes later I walked away empty-handed, convinced that my decision not to wash my hair at all is still the soundest (stopped in May of 2008).
But this is just a symptom of the larger disease: we humans can do very very little that is actually good for the environment. At best what we get to choose between is things that are bad for the planet and things that are marginally better for it.
At a global population of 6.7billion (source: the CIA World Factbook) - expected to double within the next 25 - 40 years - our biggest environmental challenge is ourselves. There are simply too many of us to survive on this planet. We are this close to using up what little there is left of the Earth's natural resources, and at that point we will be stuck.
The environmental movement, at its core, is about the preservation of the human species, as in fact are basically all major paradigms and certainly all political philosophies. Ironically, if the planet keeps becoming more and more hostile to human life, we will almost certainly experience a mass die-off (such as may not have been seen since the introduction of oxygen to the atmosphere about 2.5 billion years ago (The "Oxygen Catastrophe" - again, Wikipedia is simply the easiest source here, but this is a well-accepted scientific theory) - talk about environmental disaster!), and then the planet will begin to recover. The Earth, it turns out, would be better off without us at this point.