This article by Charles Krauthammer makes good points about the inherent tradeoffs that must occur when we seek to change our energy usage. There are always costs and/or other unintended consequences of any new law, and the government has become very adept at hiding those costs and consequences (i.e. making sure someone else gets blamed).
The most efficient and honest way to reduce gas consumption, and all that consumption entails, is a simple increase in the price of gas. Everyone sees what it costs and reduce their individual usage in response. Those who use the most pay the most. Few people can stop using gas entirely, but almost all of us could (and would) use less. Voila: less CO2 emission; less pollution; more demand for fuel efficient cars; less consumption of oil from Saudi Arabia…
The best way to raise the price is with a tax on fuel that is offset by tax cuts elsewhere, so that the overall burden of government on the economy is not increased.
Of course, the problem with this is purely political. Unlike current proposals where the real cost is hidden, everyone would see that the new costs were the result of the new law. But then Congress can probably still find some way to blame it on the oil companies or some other convenient scapegoat.