It's a big ol' truck, so it's no surprise to see the Ram 1500 make this list. Though the Ram is available with a reasonably efficient diesel option, the big Hemi V-8 with the 4x4 powertrain struggles to break 15 mpg.
A Hemi V-8 outputting 475 horsepower is equally to blame for the fastest SUV in this class' low miles per gallon and high thrills per minute. Eco technologies keep the 6.4-liter's efficiency numbers on par with the smaller 5.7-liter in the Ram.
You knew this one was coming. The Viper is so notorious for its fuel inefficiency that Chrysler tried to spin it off into its own brand to keep from hurting Dodge's fleet mpg average. But a 3-second 0-60 time and 645 horsepower have me asking, "EP-who?"
Bentley's Continental Flying Spur sedan and Continental GT super coupe actually boast fairly respectable 20 mpg highway economy averages, but these heavyweights' abysmal 12 mpg city estimates drag their combined averages down.
The Toyota Sequoia cracks the 14 combined mpg mark when equipped with the big 5.7-liter V-8 engine and 4WD drivetrain. For those who need room for passengers but not the towing capacity, the much more efficient Highlander may be a better choice.
Bentley's Phantom-fighter has fewer cylinders (eight vs. 12), but the same displacement as the Rolls. It's also down one mpg for its highway and combined estimates. To make up, Mulsanne also adds a turbocharger to boost peak output to 505 hp.
From hyper cars and hyper luxury to a white panel van?! The GMC Savana 3500 and Chevrolet Express 3500 make the list with their combined 13 mpg estimates. To be fair, most of the 3500's competition avoid this list by classifying as heavy-duty vehicles.
Ferrari's V-12 grand tourer has about 360 miles of touring range between fill ups if you take it nice and easy on the highway. Buuuut, with 730 hp and a top speed of 211 mph, you probably won't be taking it easy at all.
Take one of Mercedes-Benz' most ridiculous vehicles and add one of its most ridiculous engines and you've got the G65. This excessively overbuilt SUV boasts a 630 horsepower, bi-turbo V-12 engine. Yes, it's ridiculous, but it's also so very awesome.
This low-slung beast looks like it should slice through the air with its razor-sharp aerodynamics, but this 690-hp machine is built for speed, not efficiency. Zero to 60 mph happens in under 3 seconds with a top speed rumored to exceed Lambo's stated max of 217 mph.
For many years, the Veyron held the title of fastest car in the world, so it's no surprise that this 16-cylinder, quad-turbo cruise missile is the least efficient production car in America. I'd be willing to deal with 8 mpg in the city to get a top track speed in excess of 250 mph. Fortunately for the environment, the $2 million-plus price tag puts it just outside of my budget.