I'm with ya, all you folks who are concerned about sustainability and kind of turned off by the stereotypical trappings of the ultra-rich.
So here's my thought about reconciling the intention to prosper with the concept of what it really means to be very rich: One role that the very wealthy can play is to help bring sustainable innovations into the mainstream.
Maybe you don't care about owning 20 cars-- no need to. However, if you had that kind of money, you could afford to buy the cutting edge technology in hybrid or other eco-friendly cars.
Wealthy people buying Priuses (Prii?) when they're still new and expensive, make it worth it to car companies to keep making them, and enable them to eventually put the technology in lower-cost models.
If you're that wealthy, you can hire some of the top architectural geniuses in the world to come up with a plan for a house that is creatively, innovatively "green", which might inspire more widespread building techniques across the economic spectrum.
You can fund whole programs in research, the arts, education, health & human services. You can buy all your food from local organic farmers and ranchers, supporting their livelihood. You can offer someone you care about the opportunity to pursue their own passions without the stress of a day job, or help get exposure for their work, or invest in their dream.
I work for a large nonprofit and I can tell you that we have a handful of devoted donors who directly fund specific programs. Everyone gets a little anxious about making sure they're happy, but it's because those donors care very passionately about those projects and want to know what effect they're having. I imagine they take tremendous joy from meeting the intern they paid for or seeing the tools their money developed.
Wealthy people with a passion for social change can have a tremendous effect on the world with every choice they make-- from what they eat to what they wear to the media they consume to the people they associate with. If money is a form of energy, they have tidal waves of energy to pour into anything they care about. I find it unfortunate that so many of them choose to pour it into destructive, wasteful, elitist things; but that's not an inherent part of being rich, and I don't have to choose those things for myself.
I decided a while back that I am already a philanthropist, since working in the nonprofit world means making less than I could get in the corporate world. I figure that salary difference plus the fact that my work every day contributes to a cause I care about makes me a VIP donor, even if I don't get the elite parking.
Maybe I'm getting in the way of my own prosperity by being too excited, but I can't WAIT to do the philanthropic projects I know I'll do when I have more abundant money. They're things I try to do now in some way even if it's on a small scale, but it will be SO COOL the day I write a huge check to set a great new initiative in motion.
(Of course, I strongly suspect that when that time comes, I'll be writing that check and I won't be totally blase about it-- I'll be doing a little chair dance and thinking OMG THIS IS SO AWESOME!
I often have those experiences of "life is beautiful" euphoria now, being conscious of how much I'm loving whatever it is I'm doing in that moment, so I doubt that'll change...)