Another factor to consider for plug in hybrids is if they become very prevalent utilities might be forced to put a new meter in your house for the car and put it on mandatory time of day rates, which economically encourages one to charge it later or earlier than at 6 or 7pm whenever everybody gets home from work. Otherwise everybody plugging them in at the same time would put a lot of strain on load pockets and cause the utility to increase capital expenditures to reinforce the system unnecessarily. We are talking hundreds of millions to and easily billions of dollars to support them. Off peak charging is highly beneficial if you don't want your electric rates to skyrocket even more than they already have (in NY at least).
you east coast people don't understand. This is not an economic decision. Owning a prius is a gut level feeling of belonging and moral superiority, cost be damned. we may lie to ourselves that the cost is lower but that is OK, however, we don't like it to be pointed out to us. and we have elaborate rationalizations to "prove" you are wrong even if our math is preposterous.