Plotting my strategy in the purchase of my next Prius

The gas crisis will not change in the future. It will stay with us like a virus, dormant or active. What I believe will change, are the cars people buy. Unless the automakers or aftermarket makers come up with a technology to provide an automotive appliance to make SUV's a vehicle one can drive without emptying the wallet I see a lot of SUV owners seeing their current transportation being nothing more useful than planters for next year's flowers.
I feel so fortunate that I drove a Prius rental in April and it change my mindset on the car I wanted to own and identify with for a variety of reasons, all of them positive, I believe.
I really appreciate Prius Chat as a way to get a deeper understanding of a car that has literally change automotive technology, the old fossil technology that has remained the same for the past 100 years. This car will remain the cadillac, (pardon the pun), of alternative transportation. Hydrogen, or Plug-in technology? Can you see some some pitfalls in either? Running your car on corn, vegetable oil? I believe we will see it all presented in the next few years.
My strategy: Purchasing a Prius every four years, even years, 2012, 2016, etc...If Toyota continues to lead the automotive pack in technology and the rest follows 40 MPG in four years will be common. Will the next generation Prius average 60-80 MPG?
I surely expect the electric companies will find ways to gouge plug-in car consumers every bit easily as our Arabic friends have gouge us at the gas pumps. There is now a blueprint for the electric companies to keep transportation costs at prohibitive transportation levels and I believe relying only on one source of energy will keep the consumers victims. Terry