Mike Byrne cares about two shades of green: the kind in the forest and the kind in his wallet. So when the Rice University psychology professor and his wife, Vicky, began shopping for a new family car last fall, they were willing to consider environmental factors--once their financial and practical needs were met.

The Toyota Highlander SUV hit the sweet spot for the Houston couple, with plenty of space for their two kids and an optional third-row seat for bigger family outings. But gas mileage of barely 20 mpg for the V-6 version they wanted was a drawback. Then they heard that Toyota planned to introduce a gas-electric hybrid version of the Highlander, with the muscle of a V-8, the fuel economy of a compact, and even cleaner tailpipe emissions. So they ordered one from a local dealer, even though it won't arrive until late summer--and will cost about $4,000 more than a regular Highlander. "It will make me feel better," says Byrne, "about driving a large vehicle in a place with such lousy air quality."