The maker of the cleverchip electric assist (todd, a.k.a. tfahrner on these boards,) is well-respected here. He's been car free for a long time and (i think) is pretty savvy about the political ideals of all sorts of car-free folks.
The amount of fossil fuels used by a 100-pound power-assist bike is a pittance compared to the consumption of a 3000-pound vehicle.
If you're thinking about getting rid of one of your family's cars (I'm not sure how many you have) or just letting your car spend most of its time sitting still I think all of us here would applaud that. If a power assist bike is what makes that feasible, then by all means get one.
Electric assist bikes are not as versatile as we might want them to be, though. I think Todd's kits are more practical than most electric kits for long range and high speed commutes, but i'm not sure whether it's up to the task of a fast 60 mile round trip and you shouldn't expect top speeds much over 25 miles per hour, i think.