Is the grass truly greener on the other side?

Here's a study that suggests that gas gurgling Hummers are actually more environmentally friendly than everyone's favorite battery operated wonderkins; the Toyota Prius.

Now to be fair, the study makes some assumption that drastically bias their calculations in favor of the Hummer (life expectancy being a big one) so it's probably not an accurate analysis of their true environmental impact, but it does raise some interesting points with regards to just how green are green technologies.

Ethanol and solar are both oil saving technologies which are very costly to produce, often doing more harm than good. The corn used for ethanol devastates the nutrient content of the soil while the chemicals used in producing solar panel are highly toxic. Wind power is relatively cheap but produces limited power and takes up much more space, as well as being a risk to the local wildlife.

While we probably all agree that no matter what your stance on the global warming debate reducing pollutants in the air is a good thing, how hard should we push for the adoption of the current batch of green tech as opposed to waiting until their are further developed?