One of my engineer passengers has a Prius. If I understood him correctly, all the savings he got in gas were exchanged for the new battery (batteries?). No real cash savings. I don't know anything about the costs (real-life, not just upfront) of making and disposing of batteries. Just tossing it out.

Personally, if you've got one good family vehicle, that should be enough. You usually take the train to work, don't you?

Sue