Forbes has a short piece with calculations of the payback period for the extra cost of a new hybrid car, pointing out that as far as buying a hybrid goes,

Don’t do it to save money. At $3 a gallon for gas, it takes a long time for a hybrid car to pay back its higher cost. Buy one, though, if you have a worldview that says gas prices are going to shoot way up or if you have a philosophy that says reducing carbon emissions is worth any price.

At $3 a gallon, the author notes it would require seven to twelve years to save the extra cost of a buying a hybrid over a conventional model, depending on whether one buys a low-end or high-end hybrid. Things could get better with renewed or extra tax credits for buying a hybrid.  If gas costs go way up, of course a hybrid really begins to make a difference in savings.

Also, the article does point out that the calculus changes substantially for plug-in cars, which for short distances would require no gasoline at all.

They also point out that, even without cost  savings, with carbon dioxide reductions,

Maybe you’ll save the planet, maybe you won’t. But you won’t be hurting anything, you’ll be driving a new technology, and your neighbors will think you’re an Earth-loving, responsible fellow.

But, alas

Most buyers don’t buy cars with saving a penny as their first priority; they buy what appeals to them, be it looks, power, comfort, prestige or greenness.

One might attract more potential mates who are tuned in to this sort of thing:  earth mamas and earth papas, and hopefully practicality will become more appealing once the deluge hits.