SUVs with the Best Gas MileageWhen you're considering the purchase of an SUV, one of the chief factors in your decision-making process is undoubtedly the gas mileage of the vehicles you're comparing. Of course, this shouldn't be your only criteria for vehicle selection, but we'll get to that in a moment. For now, and to help make your search easier, here's a quick rundown of the SUVs with the best gas mileage.Ford Escape Hybrid: 31 MPG city, 29 MPG highway.Mercury Mariner Hybrid: 28 MPG city, 27 MPG highway.Chevrolet HHR: 21 MPG city, 28 MPG highway.Honorable Mention: Lexus RX400, Toyota Highlander Hybrid, Saturn View Hybrid, Jeep Compass, Ford Escape, Toyota RAV4.It's worth noting that the process of determining the best SUV for you & your needs runs parallel to that of choosing an appropriate car. That is to say, many of the same factors apply. You want to choose a hybrid whenever possible if fuel consumption or environmental impact is a concern. Two-wheel drive vehicles are more energy efficient than their needier four-wheel drive cousins - but if you're in rugged terrain for the majority of your in-vehicle time, you'll obviously want the latter. The same goes for engine size, as a smaller engine will be more efficient, but a larger engine will be able to deliver more power. The main thing to remember is, that like most things in life, balance is key. You should examine your lifestyle, and use your findings to determine how much of a trade-off you're willing to make in the size & power vs gas mileage debate.