I disagree.

People buy monster-vans because energy prices are so cheap and that they figure than once in a while they'll need the space!  Hell I've got a mid 40's (eternally) single neighbour looking to buy a SUV because one a year he MIGHT want to move some larger items that don't fit into his, current, full-sized car!  This is the same moron who complains about having to cut his grass and yet he fertilizes it etc etc!!  Note - he DOES NOT go outside of his house!!

Several friends (even Green Party supporters!) just bought a pollution spewing minivan because they had a 2nd child.  Heck, if we had a third we'd still be in a car!
But that's our beliefs expressing themselves.  Few people think about the pollution they're making, the conseques of their actions, or even think about what they need vs what they want.
Basically I see very very VERY little proof that people can moderate their wants or desires and that's the basis of destructive capitalism!  Check this out:

http://www.drmcdougall.com/misc/2006nl/february/moderation.htm

My family went vegetarian for, in order of importance:
1) the environment
2) health
3) animal welfare

but I've recently gone vegan because of #2.
Curiously enough if peak oil hit in force I would have no quams about eating some small quantity of animal products - as long as they're free range and not from modern "farms".

One interesting interview as with Dr. Davis Suzuki when they were filling in a big city hospital during a smog day.  He said that the people coming in were kids and elderly being brought my middle-age people driving SUVs.  They would all do anything to help their family members in distress - but NONE of them saw the link between their pollution spewing road hogs and the injury done to their family members  :<

I think some people need vans.  My boss has a wife, three little kids, an elderly mother, and two dogs in his household, and driving a minivan is probably a better option than taking two cars, which is what they'd do otherwise.  The days when you could throw the kids in the back of a station wagon or pickup truck are long gone.  

But a lot of people don't need them.  I have a friend who bought minivans because she had four kids.  The kids are grown and gone now, but she still buys minivans.  She likes to sit up high, so she can see over the other traffic.

I find it odd that Dr McDougall equates "passionate" with "obsessive" and "compulsive". I don't agree with that wording (you can certainly be passionate about moderation), but the general point remains.

I find it is very difficult for even very rational people to completely see the connections between their actions and their situation (to be fair I probably couldn't claim to be perfect in this regard either). My sister who doesn't (or can't or won't) see the connection between or irony of the long line of SUVs waiting to pick up children at her kids' school and the American flags and yellow ribbons on the bumpers. Thinking wholistically, let alone globally, is difficult.

Praetzel, I was enjoying your post even before you totally surprised me with your Dr. McDougall link. Congratulations on going vegan.  I've been enjoying that road for about 10 years now.  As the saying goes, there's no such thing as a meat-eating environmentalist :).  McDougall is one of my favorite (science-based) nutrition authors exactly because he doesn't accept the mantra of "moderation."  As the recent landmark book "The China Study" elucidates so well, even small amounts of animal products raise disease risk.  The American Heart Association's "heart-healthy" diet is a classic example of the failure of moderation.  Studies reveal that even when patients follow this protocol, their arteries still worsen, and they still die (though not quite as quickly).  As you probably know now, this is the kind of typically ineffective nutritional remedy offered by "modern" science, despite direct invervention studies proving that atherosclerosis is totally reversible.  A fascinating fact is that as we stumble along the "bumby plateau" of peak oil   (or even slide sharply down the curve) - a huge number of people will be forced away from massively inefficient, disease-inducing animal foods and into health-sustaining plants.  Millions of decadent and obese Americans will regain vibrant health, reconnecting with their own bodies, despite economic turmoil.  And hopefully the tremendous amounts of grain, etc., we're feeding to food animals will be redirected to human mouths, while cutting out the suffering of billions of sentient creatures at the same time.  It's a staggering and strange web we weave, indeed.