Looks to me like a number of people here have traded in there vehicles for a more economical and ecological ride. I can understand there is a lot of immediate gain when comparing an I4 compact car to a monstrous V8 truck at the gas pump and exhaust pipe. When a car is built there must be an enormous amount of energy that goes into the harvesting of the natural resources, processing, transporting, manufacturing, and toxin by products. The more non-immediate gains to the earth by keeping your current vehicle must by far out weigh buying a new one. I know this not a black and white argument but a 1997 car getting 25 mpg must be more "earth" ecological from all the factors stated above than a new 2009 hybrid getting 65 mpg. The average American switches cars every 4 years so in the 1997 vs 2009 if you were to buy a new car every four years you would have gone through three cars and all the energy to get them to your local dealer. A little old grandma driving her 1988 V8 oldsmobile 4 times a week and the hypermiler commuting 60 miles daily might burn the same amount of gas but is the negative effects to the environment from combustion enough to warrant grandma buying a new car? How much energy does manufacturing a new car take? How many gallons of gas do you need to save before this number is off set?