Steve,
Nice thoughtful post. Except there is one aspect that I thought you might address, but seems to be completely left out. That is the distinction between consuming "renewable" vs. "non-renewable" resources. Or maybe more precisely, the scale of non-renewable resource consumption.
For most of the examples you spoke of, such as an expensive dinner, expensive shoes, and expensive car, the consumption of non-renewable resources (including environmental health) is almost certainly a nonlinear function of the cost. In other words, much higher cost does not necessarily mean much higher consumption. On the other hand, a big house may result in significantly higher consumption (lumber, electricity from coal, etc.). Of course, often these potential costs can be offset by spending even more money; for example, by choosing environmentally friendly options such as solar panels on your house.
Given the strain of population growth on valuable non-renewable resources, I think it is prudent to take these considerations into account. To a certain extent, you can justify consumption by providing value, as you mentioned. But this kind of thinking is also what keeps our major corporations moving headlong toward making our environment uninhabitable by externalizing costs wherever possible.
Something to consider, at least.
Peace,
Mike
The Absent Mind