Payback Period... A Flawed Concept?

Last spring I was at an Inspire Lecture and I heard Chris Hellstern from KMD talking about a Living Building Challenge project he had recently completed and he said, ".....you know we never ask whether the granite counter top or the chandelier for the lobby pays back.  It is understood that we are required to have that."  He raises an excellent point.  As green builders we are frequently asked that question about pieces of energy equipment, ...does it payback?  At first glance the question is a legitimate one, no one wants to pay for a solar array that will not produce enough energy in forty years to pay for the cost of the equipment.  There is another subtle subtext to the question though.  The question is...  Is it worth it?  I usually hear this question from people who have already decided it is not.  I am not advocating costly, underperforming, add-ons to buildings that do not really make sense but make us feel good about being green, but I do think we need to ask ourselves what kind of future do we want to have.  What kind of buildings do we want to have represent our culture and our decisions?  Shouldn't we spend a bit more to invest in a technology or building methods that are worth supporting?  What are the choices that we are making for our buildings, saying about our values?   Are we really a culture that values only money?  Every project I have worked on has had its list of must haves.  When we include a granite counter top in the project we don't question the fact that it is not the cheapest material available, we understand that the client wants the quality that granite represents, and sometimes the client has other motivations as well!  But it seems to me that we have not looked at energy-related items like mechanical equipment, renewable energy systems, and insulation in the same way.  Those items must prove to pay back; most of the time they are included in the project or not based on this fact.  There are other important issues surrounding these decisions though, like how much can we promote and make ubiquitous, renewable energy in buildings? How can we reduce energy consumption in buildings to near zero, and what kind of legacy are we leaving?