Magnus - a nice post summarising the real situation regarding electric cars in general. I believe that they are the future of vehicular transportation - unfortunately the future is not here yet.
Local travel and short distance commuting - yes no problem. Edinburgh - a media gimmick.
The Nissan Leaf in particular is a bet on a technological experiment. Put the car out into the hands of real drivers and see what happens - pretty brave on their part.
Tesla is a slightly different approach and the jury is still out on it - as it is on all the alternative fuels.