If one car symbolizes hybrid cars in the public's mind, it is the Prius. Alongside the Honda Insight, the Prius was one of the two original hybrid models introduced to the United States. Built on a 1.5-liter, four-cylinder engine, the Prius delivers enviable EPA mileage estimates of 48 miles per gallon in the city and 45 miles per gallon on the highway.

The Prius uses a full-hybrid drive, meaning it can operate in an all-electric mode, all-gasoline mode or a combination of the two. When the car comes to a complete stop, the engine also stops, saving fuel. When it is time to go again, the electric motor takes over, bringing the car up to speed, where the gas engine can take over. Because the Prius has sold so well, no Toyota hybrid qualifies for the federal tax credits anymore.

Enthusiasts and industry observers are waiting breathlessly to see what Toyota has in store for the 2009 Prius. Speculation abounds, but official information is sparse. Rumors range from the next version including some manner of plug-in element, to even a possible solar panel on the roof that would power the air conditioning. Company officials remain tight-lipped.