I think it will be a long time before electric cars become the norm, if ever. Right now the technology just isn't there. They don't have the range to be practical and the cost is still too high. There's also the problem of the batteries. They won't last the life of the car, so besides the price of the vehicle to begin with, you have to factor in the cost of replacing the batteries periodically.
That said, I think there is a high potential for electric hybrids to take a bigger share of the market in the next few years. They solve some of the problems inherent in the electrics, in that they have unlimited range, they greatly increase the mpg and cost is more inline with conventional technology cars. They also don't have as many batteries to worry about.
It will be interesting to see if they can make all electric cars more practical in the next decade. I don't really see it happening though.