An interesting post from John Voelcker at Green Car Reports discussing the inevitable tipping point. Using historical data, they project 2020, but due to the Obama Administration's battery technology research investments, it may in fact come sooner:
This is a great interview:
"The Volt is going to see significant cost reductions. We look at (battery) cost per kilowatt-hour. There are 16 kilowatt-hours on a Volt. When I first came, it was over $1,000...