Biofuels are an enormous con.
<a href="http://www.physorg.com/news4942.html">They need more input energy than they give in output energy</a>
Crops before WW2 were not produced with the kinds of extremely intensive (petroleum derived) pesticide and fertilizers regimes that have become ever more popular since the end of the war. IIRC crops produced in that manner can be sustainable for biofuels in and of themselves, without taking into consideration the deforestation, etc that normally goes before... So we need to
green the Sahara, basically...
or wait for it to green itself? 
I've read better sources on this issue, but a quick googling gives me
this document whose last paragraph tells you that, for US on-farm production in 1977, there were 10 calories input for every 1 calorie output in the food supply. (The second to last paragraph is interesting as well - marketing food consumes 1.8% of total US consumption of energy??? hmm. o_O)
10:1 is a very much understated figure, if memory serves. Figures I've read elsewhere range from 30:1 to 55:1.
Biofuels need enormous amounts of fertilizers and pesticides to be grown in an industrialised manner. The inputs and outputs don't work... Umm.. didn't that even get into an episode of The West Wing once? (The Corn Pledge?)
Oh yes!
King Corn - hardly the best of sources, but still.
The price of oil goes up, the price of pesticides, fertilizers and the fuel to move produce around goes up, hence the price of basic commodities sky-rockets... Including... Biofuels!
Anything that depends on cheap oil in it's production cannot be an alternative to cheap oil.
All of this, really, is back to
Peak Oil.
Solar, wind and nuclear - mostly nucular (
) as it stands - are the only options available to conserve the remaining cheaply accessible fossil fuels we have as a means of producing plastics, fertilizers and pretty much all of our oil-dependent products... won't happen though.