True, the sitting gas could certainly be a problem. But it would be a problem that the consumer caused. You don't HAVE to charge the car every night. Let it run on the motor every few days to keep it circulating. A gas motor that just sits and is never used will of course have problems.the gas in the volt will sit there forever and i dont know how long it takes for sitting gas to mess with an engine but i am assuming not super long. give it a few years before you decide to buy.
I will say, I have a small problem with the "give it a few years" mentality. If everyone gives it a few years, no research and development will be done, that stuff cost money, and without any income from sales of cars such as this... well, in 15 years, we will still be in the same situation we are in today. Everyone will still be griping about the price of gas and everyone will still be waiting a few more years...
You can bet Toyota engineers are looking for ways to further their hybrid designs and are probably looking at "gas free" vehicle designs as well. Why should GM be left out? The only way they will, is if we, the consumer, leave them out.