There's so much misinformation in this thread.
First, the Volt is nothing like the Prius. At all. The Prius is mainly a gasoline-powered vehicle that is supported by an electric motor and battery pack. The Volt is a battery-powered vehicle that uses electric motors as its main source of drive power, and the gasoline engine is used almost entirely as a generator to replenish the battery pack. The concepts are completely different.
Second of all, this is a first generation vehicle of its type, with a battery pack of a size and type that is unheard of in automotive applications. Its expensive because of that. The most expensive single component in the vehicle is the T-shaped battery pack that runs down the spine of the car. (I've read that its somewhere around $20k just for the pack.) Its LiOn instead of the NiMH that Toyota and others use, and its extremely power dense for its size. Being the first ends up costing a lot of money, and that's why the Volt is so expensive. Or to put it another way, GM saw the market moving to LiOn batteries in the future, so rather than wait for the market to catch up and produce suitable packs, they designed them themselves.
Last of all, the development of the Volt will make batteries in future eREV electric vehicles and hybrids much more cost effective, and longer lasting. LiOn batteries are much, much safer and less toxic than NiMH batteries, and they have the capability to hold more juice in smaller spaces. You also have to understand that rolled into the Volt's price are all of those development costs, which other models will not have to bear.
Oh, and anyone that thinks this project was a result of government intervention in GM is a fucking idiot. It started development in 2006 and was approved for production before GM went bankrupt or took any funds from the government. (production was approved in September 2008, and they did not ask for any funds until November)