The national average for gasoline has topped $4 a gallon for the first time ever, and gas prices in Chicago seem to start at $4.25 and spiral upward. Thus, cars that can achieve 30 mpg or more on the highway are becoming increasingly popular. This year we have 45 cars and two SUVs on the list. The car with the best overall gas mileage is the Prius hybrid with city/highway fuel estimates of 48/45 mpg. The non-hybrid car with the best gas mileage? The Toyota Yaris with 29/36 mpg. From compact hatchbacks to family sedans, you're sure to find a car on this list that will suit your lifestyle.