The right battery power is the "holy grail" for electrics of all types. The F3A boys have not waited and have long adopted li poly's for their 2 meter ships. The "right battery" will probably kill combustion engines as we know it. Combustion engines are about 20% efficient at best. Well designed electrics hover around 85%!! Only about 1% of the power of a combustion engines is actually used to move the driver. The rest is wasted as friction, mechanical losses and moving the weight of the vehicle. That said, you will will have to pry my Saito's from my cold dead hands.

Hydrogen is a great fuel, for space shuttles mostly.  For cars, planes, etc. the fuel tank is just too big or expensive to make it economical.  Not to mention how much energy it takes to produce the hydrogen.

Some simple energy calculations:  electric power plant turns about 40% of the energy in its fuel into electricity.  Transmission losses, say a hundred miles to your house, are another 10%, down to 36% of the fuel energy.  Charging your electric car loses another 10-15%.  Down to 31% overall efficiency.  Then the electric motor in the car gets about 80% of the energy to the wheels- 25% overall efficiency.  Compare that to the fact that a typical car puts about 25% of the energy in the tank into turning the wheels.  So fuel to wheels an electric car is only around 10% at best overall more efficient than just burning the gas in an IC engine-powered car.

If you want real efficiency(not economy) and minimal fossil fuel use, get some solar cells installed and use them to charge your Toyota Prius.