Improved fuel efficiency has become an important part of many consumers' car-buying plans, and for some "gas mileage" is at least as important as horsepower and style.

For those shoppers, or anyone who values squeezing every last mile out of each gallon of gasoline, the elite 40 mpg club is a good place to start looking.

These are cars that deliver at least 40 miles per gallon fuel efficiency on the federal EPA's highway test cycle. (Sorry, no trucks yet.) At the moment, the numbers are small, but club membership is growing, albeit slowly, thanks to advances in engine design, aerodynamics and lightweight materials. These help automakers overcome their vehicles' inherent handicaps of engine inefficiency, aerodynamic drag and weight that that saps fuel economy.