I assume that you guys have seen the Tesla Roadster (http://teslamotors.com).

What I'm hearing from them is that the critical feature that is holding electric cars back is the power system. This field is pretty experimental but someone who could come up with the magic battery that charges in 5 minutes would probably have a valuable system on their hands.

Another angle would be to have cars that run on batteries that can be swapped out at gas stations as needed. There are a bunch of issues that need to be considered for this approach but it's still a neat idea.