And in my calculus, besides the cost-per-mile, there is also, uh, the planet. Not to sound too sanctimonious, but that's definitely a big deal for me, as I love her dearly and am keenly aware of how I participate in the Great Plunder of consumerism. I even have a sign on the back of my electric bicycle: "Oil Is For Sissies." I know: obnoxious!