Hybrid technology breaks the link between great fuel efficiency and the stripped-down econobox of the 1970s. Thanks to hybrids, and plug-in models rolling out in the next year or two, car buyers with deep pockets no longer need to compromise on ride quality or luxury features in order to save fuel and protect the planet. On the other hand, hybrid and electric car makers have a habit of emphasizing large engines and raw speed when thinking about luxury buyers. We’ve yet to see a hybrid or clean diesel car with great luxury features, but with a right-sized four-cylinder engine that could send fuel efficiency into the 40-mpg range. If it comes out, we’ll add it to our luxury hybrid list.