Hydrogen is a non-starter for many reasons, one of them being energy density. No internal-combustion engine will ever be efficient on hydrogen due to its ridiculous heat cycle, but fuel-cells can be efficient on it. Reformers are available to liberate hydrogen from various fuels, but the sad fact is that the large amounts of energy available in fossil fuels are due to carbon, not hydrogen. Carbon fuels are energy dense. Coal has a lot of energy per mass. This is also why diesel outstrips gasoline in terms of miles per gallon. Diesel has more carbon.
Anyway, the idea that we're running out of fossil fuels is absurd and irrelevant. Absurd because known resources would last us around a hundred years at the current rate of growth of consumption and irrelevant because as fossil fuels become less prolific, some other energy source will be developed as it becomes comparatively more cost-effective. In other words, as you point out, hydrogen is not a silver bullet. A synthetic carbon fuel could be produced by reforming CO2 and H2O, and would accomplish nearly everything that H2 can accomplish with the added advantage of higher energy density. And, for you global warming nutters, it would recycle its own carbon, as if it matters.
As you can probably guess, I'm of the opinion that global warming is ridiculous. Or, more precisely put, anthropologic climate change is not happening. First, the contribution to the environment caused by man is not even within an order of magnitude of that caused by a single volcano. Second, if the system really were divergent, it would most certainly have diverged already. However, geology shows us that it has always converged, even after the ice age.
As for bio-mass fuel, there is no discernible difference between bio-mass fuel and solar power. As a matter of fact, all 'renewable' energy sources are solar based except tidal power. Wave power comes from wind, which comes from convection caused by solar radiation. Wind power is more direct. Bio-mass is made of plants grown by solar radiation. Bio-mass is also hideously inefficient. While it is quaint and in vogue to think of natural processes as superior, the simple fact is that your average plant is less than 1% efficient in producing power. In other words, grow a plant that yields a high oil yield (hemp isn't it; you need a seed like sunflower seed or something like that) then process that oil into bio-diesel and the resultant bio-diesel will have less than 1% of the energy the plant absorbed. Alcohol is even less efficient but uses more of the plant, so it stays competitive. Essentially, you'd have to annihilate the entire plant to achieve anything near useful efficiency, and that'd still be around 2-3%. Compare with nearly 30% for the latest solar cells and you see why plants are next to useless for energy production.
Which brings us to the real reason people are so bullish on hydrogen: it can easily be produced with saltwater and electricity. Saltwater is readily available and next to free while electricity is the result of those highly-efficient solar cells. Electrolosis-produced H2 is very efficient comparatively to bio-mass, meaning that for a given area of production, solar cells and H2 make a reasonable efficiency rating, closer to 10% or so, 100-fold improvement...
The problem, of course, is that solar cells are a)expensive and b)energy intensive to manufacture. They also wear out. So, those expensive and efficient solar cells are actually a net energy loss right now. Cheaper solar cells are energy gains, but the energy cost of manufacture eats into efficiency. Also, the cost of such a system, even using normal solar cells, would be prohibitive. A simple system to power a small RV with no airconditioning runs into the thousands of dollars. To run an airconditioner for a reasonable period of time would require a system that wouldn't fit on the roof of the RV.
And that's another problem with solar energy: either you paper the country with solar cells in the hopes of getting enough energy to possibly meet the energy budget (still possible, but not for long and only if you paper every square inch, including oceans) or you accept a seriously lower energy budget to use bio-mass. Remember that you have to grow all that bio-mass by hand rather than with diesel tractors because if you use the tractors, you've got a net loser already because it takes more fuel to cultivate that patch of land than the patch of land will ever produce. Heck, you've got a net loser, anyway, because doing farming by hand without fertilizer (another huge energy cost) means that your yield will be hundreds of times lower than it would otherwise be, meaning serious loss in food production. You'd be lucky to feed yourself and produce maybe 40 or 50 gallons a year of some sort of fuel, just enough to get to the market and trade your homemade bangles for someone else' homemade baubles. Oh, and non-farmers will starve.
As for mass transit, it's a non-starter, too, except in certain very narrow situations. First, if the town is simply too dense for proper roads, mass transit makes sense. Short runs at low speeds are cost-effective and convenient because the conveyance can be operated at or near capacity, meaning that the efficiency actually shows up. This almost never happens in the US. The other case is a situation where one large metropolitan area needs rapid access to another. Here, trains work well and are cost effective as long as the passenger load is high. Japan is an excellent example. However, train cost is largely in rail maintenance, which is related to the length of the track, so the metric that determines cost-effectiveness is passengers per track mile. Japan and Europe run a lot of trains all the time with good passenger load on their tracks. The US, however, has a routing nightmare, being neither long nor particularly logically laid out, meaning that we've got a lot of random directions to the next city and vast distances in between, meaning that, unless the entire population of Topeka, Kansas commutes to Dallas for work, there's no reason to build passenger rail between the two. That's why we use airplanes, whose primary operating cost is measured by passengers per time in service, not distance of static route, so a given aircraft can handle any number of routes meaning it can handle the load for several routes and thus be much more cost-effective than rail.
A simple case study is a transit bus. On a whim a while ago, I bought a transit bus, a GMC RTS-II-04, 1983 model, 597,000 miles on the odometer. It was powered (I subsequently came to my senses and sold it) by a Detroit Diesel 6V92 T/A turbo-supercharged six-cylinder diesel that got about 330HP and 800 pound-feet of torque. It also got all of 8MPG at 55MPH but around 3-4MPG as a transit bus with a lot of starts and stops. My car gets 29MPG at 87MPH or around 17MPG with a lot of starts and stops.
Now, a common commute in a car may be half an hour and cover perhaps twenty miles. In my car, that costs about 1.2 gallons of gasoline. The same commute in a bus would run about an hour (starts and stops, remember) and cover twice the distance (they're going to a lot of different places): 10 gallons of diesel. Diesel is something like 20% more powerful than gas, so that would be around 12 gallons of gas. That's ten times the gas cost already. However, consider that that bus will likely dead-head back because most people commute one way and you've got to energy-justify 24 gallons rather than 12. Even if you let it run instead of stop and start, it'll still be around 16 gallons. That's around 15 times as much fuel. My experience on busses tends to indicate that they average fewer than 15 people on board most of the time. Sure, the high-traffic routes average more (see first case above) but the average over the whole system is less than 15. I'd guess around 10. So, for a net loss in energy, you're wasting 40 minutes a day of everyone's time...
And, this analysis doesn't even touch on the question of salary for the driver and lost time for the users. Just the driver alone will be receiving around $30k a year, which he will use to buy goods and services which themselves use energy, meaning that any true analysis has to take into account the energy he consumes as well as the energy the maintenance depot, managers, so on consume. If those people were put to other uses rather than transportation, their energy would be better spent.
Anyway, the fact is that any modern economy is 90% energy at its heart, so something that is cheaper is almost invariably less energy-intensive, as well, so the fact that, without government subsidies, most mass-transit efforts would die tends to indicate that they are more energy-intensive than the alternative.
And, yes, I'm a libertarian.
I'm not doing this again; last time no one believed it.