This is not such a silly thread, in about 10 years time the amount of oil left in the world will really start to diminish.
Alternative fuels will be all that's available, unless you wish to spend plenty of money for standard petroleum products.
I personally believe that we will have another decade of buying whatever kind of bike we please and ride it how we wish. After that, more and more draconian measures to conserve the remaining oil reserves will start to be upon us.
Diesel bikes will start to appear more frequently than the three commercially available ones of today.
Check out:-
www.centaurus.de
It's a 2 cylinder Diesel bike of 851cc you only get 125 Km/h top speed but with the 14.5 litre tank and 2.5 Litres per 100 Km you'll be able to travel about 580 Km before refuelling.
One of the interesting aspects of this bike is that it appears the gear change is on the right hand side, which means it cannot be sold in the USA, unless I'm wrong.
It really is the future for cars, bikes, trucks and whatever, whether we like it or not. Unfortunately I think it'll happen in our lifetime so I intend to do some serious travelling in the next decade on my bike whilst I can still blast away.
Mick.