I think there are multiple goals for different people. While it's a worthy goal to conserve natural resources, I bought a Prius because it's reliable, comfortable, and can save me money on gas compared to just about anything else that would have been practicable for me.
Just getting around to this... and every few years, new car technology/design comes around to give you a fuel economy boost that you would have gotten from hypermiling anyway. Who knows, Toyota could make a basic hybrid in 3 years that EPA rates as 60 mpg city. (Or just get a 1st gen Insight.) So I agree... as they say in the northeast, just drive d'cah.