If we didn't already have the Honda Civic Hybrid (which get fantastic gas mileage) I would porbably be signing up for one of the new 2008 smart Passion coupes. I owned a 2003 smart Pulse coupe for several years and really loved it (it got up to 55 mpg) and the new version is larger and has more hp (slightly less gas mileage at up to 45 mpg) but still that is as good as you can get from a normal gasoline engined car (especially with an automatic transmission).
My next car purchase might be the new Honda FCX-V4 Hydrogen Fuel Cell car which will be available within 4 years or less ( it really appeals to me to be totally pollution free in sofar as my vehicle).
"Oh My Gawd"
I might be a closet Tree Hugger!