Last week, the Detroit Auto Show featured a bevy of leaner, greener machines, but what I enjoyed most was the upped efficiency of traditional cars. I know that it’s not purely consumer demand driving the added mileage, but governmental regulations that have automakers keeping far closer tabs on the cumulative mpg of their offerings. Hey, whatever it takes is fine by me.

A prime example is the zippy, new Chevrolet Sonic. A compact car in sedan and hatchback styles, the Sonic will become available later this year as a 2012 model. It’s biggest draw, however, is its ability to eek out 40 mpg on the highway… that’s right up there with the mile-per-gallon boasts of alternative powertrains. At a far lesser cost.

To sweeten the deal, the Sonic will be manufactured in the U.S. – specifically, in Michigan. According to Chevy, they’re the only company building a small car in America. At a competitive price (and likely to hit the market as gas prices rise), the Sonic has a good chance of catching on, and finding its way into more driveways than its predecessor, the Aveo.

Like I mentioned, I love seeing the enhanced efficiency of traditional gasoline-powered engines, but what I’d love even more would have been greater, realistic electric vehicle options. What’s your take? If you’re shopping for a new (or used) car this year, what factor means the most to you? Great mileage? Supporting advanced eco technologies? Or saving a buck?