As far as the recreational uses for bigger vehicles, I'm not arguing whether for some people, a truck or SUV is the best possible choice. But for many, owning a truck is nonsense. For instance, I know one guy who owns the biggest Dodge pickup made because in October, he needs to trailer his boat from the marina to a storage place, and back to the marina in the spring. The rest of the year, he crawls to work in traffic, getting 14 mpg. Forget that "he can afford the wasted gas" - that's not relevant to what's in the next paragraph.
*This* is the point, Jeff: You're only thinking about what you've been told to, or what's most prominent in the news. Forget global warming. Forget predictions about how much oil is left. Bigger vehicles cause more local air quality problems. Not in all places, because other factors determine whether the junk in the air sticks around in higher concentrations, but still, it cannot be debated. THIS is why it's irresponsible to own vehicles larger than we need. It affects everyone RIGHT NOW, and there is no question about that.