Hmmmmm....BioDiesel.
I love that stuff, I run it in my 5 gallons of it in every tank in VW Golf. The car runs quieter and the exhaust smells much nicer.
Add in the fact that it can be made from and vegetable oil - even after it's been used by McD's to make your lunch.

It would be nice to have it more available, as it is I head 90 miles north to fill eight 5 gallon tanks which will last me 4 months or between 5600 & 6400 miles (depends how heavy on the go-fats pedal I press).

There was a paper on this site http://www.unh.edu/p2/biodiesel/index.html that compared the cost of Hydrogen and Biodiesel. It estimated that it's going to cost ~$170billion to put in place the infrastructure to distribute (no mention of production) hydrogen.
While for the same money it would be possible to put in place infrastructure to produce sufficient BioDiesel to supply the American transport industry. This is done using Algae ponds at wastewater treatment plants and not farm land. Note BioDiesel would be using the existing gas/diesel distribution network.