Over the past few years, hybrids have hit the mainstream. There's no need to dress in hemp tunics anymore just to drive one. Almost all of the major manufacturers offer some kind of hybrid vehicle, and most of those who don't are within a year or two of having something hybrid in the showroom.

Hybrids are now the fastest growing segment of the car market, thanks to technological improvements, cost reductions, and continuing consumer concern about the stability of gas prices. Sales continue to climb each year and some models, like the Toyota Prius, had waiting lists when gas prices shot up. Hybrid owners are quick to tout the benefits of hybrids: increased MPG, decent resale values, lower carbon footprints - all with repair costs that, so far, anyway, are about the same as traditional cars.

While the first two hybrids to reach the U.S. market (the Toyota Prius and Honda Insight), were designed as hybrids from the ground up, the trend now is to add hybrid technology to existing car models - the Nissan Altima, Toyota Camry, and the Ford Fusion, are examples of this development.

The good news is that the competition among automakers means more choices for car buyers, and downward pressure on hybrid prices. There are now roughly a dozen hybrids available, with an equal number of new models coming in the next year or two. You can buy a hybrid as small as a Honda Civic or as gigantic as a GMC Yukon. The laws of physics still apply, though. So the bigger and heavier the vehicle, the worse mileage you'll get (even if it is improved), and the bigger your carbon footprint will be.

In fact, you'll notice that some of the ginormous hybrid trucks are able to claim huge percentage improvements in fuel economy. But that's only because their MPG numbers were so low to begin with. Going from 12 MPG to 15 MPG is a 25 percent improvement! Yeah, but it's still lousy. So unless you really need a huge vehicle, we recommend you still avoid buying a bigger car than you need.

Will hybrids continue to grow in popularity? Much depends upon the price of a gallon of gas in the coming years, and whether other, better technologies emerge. But the fact is hybrids are pretty good options right now. A hybrid offers everything a traditional gasoline vehicle offers, with (in many cases) significantly higher fuel efficiency. They do cost more, but if gasoline goes back up to $4 a gallon - and it likely will at some point - they'll pay for themselves pretty quickly. And if that's not enough, hybrids are also a relatively painless way to reduce your car's carbon footprint, too. And that'll allow you to walk around with a wonderful, smug feeling at the next Sierra Club composting party.