I commute 10 miles, round-trip every day. If Progress Energy were to offer a discounted rate on the off-peak charging and paid me a premium when they used energy stored on my battery during peaks I would consider a plug-in hybrid.
I don't think I would want to be "the first on my block" to try this. Like in all things I do, I would insist they show me real numbers before I made a decision. They would have to answer a lot of questions about the cost, life, storage and disposal of the batteries.
One thing I like about this idea is that it's really a "flex fuel" vehicle, if the grid power doesn't make sense financially I just don't plug it in and run it off gas. (I am assuming that the design would allow for the batteries to be removed for "normal" hybrid operation.)
I have worked around cars my whole life, from classic muscle cars to modern high performance cars. A plug-in hybrid would be great to have.
It's when idiots that don't know the first thing about how a car works or the amount of energy required to move one start talking about "500 mpg" that my guts churn.
Almost as much as the idiots who say "Hydrogen comes from Water"