Currently gasoline and diesel are the preferred method. Ethanol and LP have some popularity. But a common problem they all have is that the method of converting the energy to usable power is horribly inefficient (the most efficient reciprocating engine in the world, a diesel ship engine, is around 50% efficient).
Electric as the final drive is extremely efficient (over 90% IIRC). It also has multiple methods of portability for its energy source. Batteries are the most famous, but I don't think battery power is going to get good enough and cheap enough any time soon.
Honda has been running some full-size hydrogen cars in California for a while in a limited release, and the drivers love them. The hydrogen goes through a fuel cell and produces electricity for the motors. Fill-up takes as long as a regular car and costs about the same as gas. They have the range and power that we're used to in a regular car. They also require a lot less maintenance than a regular car. They fit most of the criteria to become successful in the market on their own.
The problems: They're still expensive and the filling station infrastructure isn't there nation-wide (only a few in California for this limited release). Honda hopes to have the price down to decent retail levels and start mass production before 2020.
I'm also thinking that if hydrogen takes, off, a home fill-up would be great. It would be a small appliance that would take your household water and electricity to slowly produce hydrogen, and pump it into your tank overnight. You vent oxygen out to prevent fire hazard, and don't actully keep pressurized hydrogen in the appliance. Of course put an O2 and H sensor on it, with a mechanical interlock to turn it off if levels get high or the sensors die. With the car's almost 300 mile range, most people would never have to fill up at a station.
BTW, there's your prior art if anybody tries to patent something like that.
Open-ocean farmed genetically engineered saltwater algae biofuels are the most likely long term solution. Petroleum originally comes from saltwater algae. We can grow all our own petroleum using less than 2% of the ocean surface. The land, water, and sunshine are free. The growing process creates a CO2 closed loop. The main danger is how to kill the superalgae if it starts growing uncontrollably. We could end up with the entire ocean covered with 20 feet of algae oil.
Hydrogen energy density is too low to be practical as a transportation fuel. And hydrogen spills go up into the atmosphere.