If you truly believe that we are nearing the end of the oil supply you should use as much as you can to usher in the capitalistic need/demand for alternatives rather than relying on altruistic motivations. The former gets results, the latter just feels good.
Whether now or later, every drop of oil will be used so these conservationist efforts are only numbing or distracting the market as to the true need without actually helping the environment in the long run.
Save the earth, buy a Suburban