A plugin hybrid is perfect for me - I have a 8 km commute to work. I could also plug it in at work. On my average day-to-day driving, I would not be burning a drop of gas. Only time would be when I have to travel a little longer - visit parents (18 km one way), or long-distance trip. I think the idea is brilliant - if they could adapt it to minivans - store the batteries under the floor.
My commute is 13km each way and I have free charging as well. Still, I would not, at present technology, buy a plug-in. The initial cost overlay, weight of the batteries, and effects of temperature up here in 'nada lessen the electric-only range (yes, even in a plug-in). Even if you didn't use a drop of gas, a particularly efficient hybrid that would average 4L/100km would be more economical than spending an additional $6-8k (or more) for the plug-in experience. Then on top of that, you'd have to pay another $4k for the installation of an at-home charger...which may or may not be vehicle specific. So, if you were to replace your car in 3 years (lease) or even 15 (drive it into the proverbial ground), you'd have to swap out chargers at another $4k. Then factor in the cost of electricity, which is not 'free' (unless supplied gratuitously by a third party), and the money just doesn't pay.
Also, the thought of never using a 'drop' of fuel isn't necessarily true either. If you floor it in a plug-in, even in "EV Mode", the gasoline engine will kick in to give you the power you rightfully deserve.
Traditional hybrids are great compromises between weight penalty, fuel benefit, and in some cases, performance benefits. All that at a far more reasonable price premium, and no need to charge 'er up.