Hydrogen should be thought of more as a battery and less as a source of power. Electrolysis is not a perfect system and energy is lost in the process, not gained. You still need some power source to operate the electrolysis.
Yes of course, and that energy can be easily supplied by wind power alone.
The catalysts used in the electrolysis are stuff, I'll admit, but it still works and can be done. Un-catalyzed reactions need a huge amount of electricity to get going, but this can be produced using, again, wind turbines on site. I leave solar panels out of the equation because they are brutally expensive and inefficient. Wind turbines are cheap, easy to set up, and can operate almost everywhere. You'd be surprised but these things produce massive amounts of electricity, and most of the time they can't work because the wind is too strong. If they were to keep up with the wind, they'd be producing too much electricity. Link them up to an electrolysis reactor and you get the conditions needed to cleave H2O into H2 and O2. Another thing is Hydrogen reacts extremely slowly with oxygen, believe it or not, unless it's a combustive reaction.
For cars, you can get compressed hydrogen fuel tanks. It's been tested and in the case of a leak and ignition source, the hyrdogen burns upwards safely without an explosion occurring or anything. Gasoline on the other hand spreads on the ground, lights up and you get a fireball. The small tanks used to store hydrogen in cars are also rather light. The only issue is the weight of the tank.
Bulk hydrogen transportation is the major issue, and the current simplest ways of dealing with it is to produce hydrogen on site (at gas stations) or to find better ways to transport it. Small hydrogen tanks for cars work, sure, but then you supersize it to truck loads and you start getting weight issues and dangerously high amounts of hydrogen. Some ways of dealing with this which are being researched actively are metal hydride storage methods. There is actually a research group at my university looking into it and they have produced some fairly awesome hydrogen "sponges", and are now simply fine tuning the production ratios to get something like 10% hydrogen by metal hydride weight compounds (which is insanely high mind you, that's a higher hydrogen density then liquid hydrogen). Such compounds can be reused over and over, you could also use them to make extremely efficient hydrogen cells that can store a large amount of hydrogen and keep a car going for a long time. The only problem is the material is toxic, so you need to take precautions, but in terms of efficiency it's insane. It's a very viable method of transporting energy.
I will admit, there is nothing more efficient then gasoline, since gasoline is a prepackaged energy source that just needs a little purification and off it goes. We'll just have to suck it up and start working a little harder for our energy, not that it's that hard.
I mean the sun is practically a source of free energy for forgets sake.