As we often point out - in fact we did just yesterday - energy efficiency is a low-hanging fruit that we need to grab with both hands. The amount of energy that we're wasting is simply too big to ignore, and by cutting down on waste we'll cut down pollution and have a much easier time transitioning to clean sources of power. But if rather than simply making what we have now more efficient, we switch to something else that simply doesn't require energy from polluting sources, or requires a lot less, we get into another very important concept: Demand destruction.
Daniel A. Gross has a great piece about it at City Lab. Here's a choice cut that says it all:
Demand destruction occurs when you eliminate or substantially reduce the need for the resource on a near-permanent basis. Somebody trading in a Chevrolet Malibu for a Nissan Leaf won’t be buying any gasoline for the next 10 years.
And I'd say 10 years is conservative; chances are, the people who are buying electric cars today won't even go back to internal combustion engines ("once you go electric, you don't go back!" should be the industry's tagline). In a decade, electric cars should be a lot better and a lot less expensive, and oil prices should keep rising too...