While I agree that an electrically-powered helicopter offers many advantages, and I personally think the hybrid idea is jolly exciting, it is important to remember that most electricity is generated from fossil fuels. Assuming battery technology improves massively, and we can store a useful amount of power in a usable weight, that battery still needs charging - where does that electricity come from? If it's out of the wall socket, ultimately it'll come from fossil fuels.
The other thing to bear in mind (and this is something the current crop of electric cars are running up against) is that you're probably going to need a fair amount of power to run your electric helicopter. Assuming you have somewhere to store said power onboard (whizzy batteries or whatever), you still have to get it in. The capacity of the average household outlet might get you fully charged up in a couple of days, perhaps a week or so - not exactly convenient (endurance of, say, 3 hours per week)! Assuming you have access to a properly meaty supply, and the various connectors and lines to get it to your pad, you're effectively tied to a single base (almost nobody else will have the necessary setup). The hybrid idea is nice, as the necessary infrastructure is already in place, but for fully 'leccy choppers to really take off (ha ha), you need quite a lot of infrastructure upgrade.
Sadly, as much as I'd love to see a proper helicopter based around electric motors, I think there's a bit of a chicken and egg problem here. Any suggestions as to how that can be overcome?