Porsche Boxster*
Mileage: 23 mpg combined city/highway
Starting price: $45,800
The Boxster roadster has a 2.7-liter, 245-hp, six-cylinder engine that nevertheless gets a respectable 23 mpg combined, including 29 mpg on the highway, Vincentric said. True, the Boxster and its hardtop twin, the Cayman, are expensive, but that's better gas mileage than many cars that are nowhere near as much fun to drive.