Hydrogen separation is a very expensive process in terms of used energy. Not a lot of people know this, and the question goes why?
When thinking about fossilized fuels and their replacements in the cars, the oil is, at the moment, still the most efficient way to deliver energy from the engineering point of view. Replacing gasoline with ethanol is an interesting question, since the amount of energy within the the fuel is greater in gasoline, and in order to do the same amount of work, more ethanol has to be burned, negating the effect. Should the motors be optimized for ethanol, I'm not sure what would happen. In principle, the energy density is less which should dictate unless the combustion efficiency can be radically improved when using ethanol.
I actually don't think that electrical cars will make a breakthrough, unless the car is needed for transportation inside the city. Elsewhere it is not feasible with the current battery technology.
Hydrogen cells might work best, but the problem is the volatility of the hydrogen, and for that reason they need to be tied to some other material that adds considerably in the weight. I think that the future will likely be in the direction of hydrogen, once the separation issues and safety has been solved at some level.