Some people repeat a particular word ("hydrogen" or "solar" or "ethanol") as if it were a mantra and promulgate it to the exclusion of all else. Arguments such as hydrogen vs ethanol miss the point. "Hydrogen" is an element, not a technology. Hydrogen requires a whole group of technologies  (production, distribution, storage, conversion) that must be developed together in order to have a real solution. Ethanol is one of a number of possible bio-fuels, each of which can be produced a variety of ways with varying degrees of energy payback. 
The tendancy to look for one magic bullet is a result of the wrong mental model. In my opinion the better mental model is to think of 25 different technologies each providing 4% of the solution. Of course, some technologies will help more than others, but we need to consider a wide variety of alternate energy sources, improvements to conventional sources as well efficiency improvements. In nature, a healthy ecosystem usually has a whole bunch of interconnected processes, not a single process repeated everywhere. Our energy infrastructure should be the same.
5 - We need a wholeclip of "Magic Bullets"
FREE ENERGY! Limited time only! Call now! There are a lot of claims of free energy, double your gas mileage, etc. that range from dubious to outright scams. If it looks too good to be true, it probably isn't true. Even honest, reputable people sometimes get so focussed on their particular product that they come to believe it is THE answer to all our energy problems. You need to apply a little realistic analysis to claims, particularly when dealing with "true believers" of a particular technology.
1 - We need Hope, not Hype
2 - Beware correct, but irrelevant, statistics
A corallary of the preceding point, people trot out statistics that sound really impressive but don't really mean anything when you analyze them. Two of my favorites:
3 - Be afraid of fear mongering
Sensational stories of the impending apocalypse make great headlines (which is why the media report them so enthusiastically). I've been around long enough to experience several "end of the world" cycles regarding petroleum. In 1974 the world was going to be out of oil by 1985. In the early 80's a popular prediction had civilization collapsing by 1994 due to lack of oil.  In 1999, when we were filling up at $1 a gallon, a heard a number of people say "those environmentalists are wrong about everything". In the long run, overly sensationlistic predictions that don't pan out hurt rather than help the cause.
Fear can be a powerful tool for motivating people to do something, but is often detrimental when it comes to deciding what to do. Describing things using the scariest possible language can lead to poor policy decisions. Witness the movement to ban dihydrogen monoxide (check out and then look at the end of this page). Look past the language and understand what is really being talked about.
6 - Understand where your priorities change the answer
People talking about AE usually mention a number of motivations involving the environment (local pollution, habitat loss, global warming), national energy security (we import 2/3 of our oil) and cost to the consumer. While all these factors warrent a look at alternate energy, they do not necessarily lead to the same conclusions about particular technologies or policies. For example:
Case 1) - If low gasoline prices in the short to medium term are the top priority, then the current oil policy may be largely correct. No energy source I am aware of has a production cost as low as a barrel of oil from the Persian Gulf. Sink a well a few thousand feet down, rig up pipes to it and get 10,000 barrels a day of wonderfully useful liquid hydrocarbons. Keeping friendly governments in power in that area (which seems to be the current US policy) makes a lot of sense. Of course, in the long term, demand will exceed the supply capacity even of a friendly Saudi Arabia and then we have problems. If an Islamic revolution makes Saudi Arabia unfriendly then we have problems sooner.
Case 2) - If increasing the USA's energy independence is the top goal than an obvious strategy is to increase the use of coal. We have hundreds of years worth of coal and technology to produce liquid fuel from coal has been around for a long time (the Germans ran a good part of their economy on synthetic fuel during the last couple of years of World War 2). The problem is that the costs will be high, both in terms of money and probably environmental impact.
Case 3) - If reduced environmental impacts are top priority then neither coal nor petroleum are likely to be favored. Major concerns include being "carbon neutral" and having low impact at the production site. Ironically, the second issue often causes serious objections to real industrial scale alternate energy projects. AE in theory is OK, but devoting thousands of square miles to biofuel production or building a major windfarm is not.
There are some things, such as improving efficiency, that can help in any of these cases. But many of the other technologies and policies involve making some trade-offs. The first step is deciding the priority among a number of reasonable goals.
Framing the Argument
Common errors and pitfalls in alternate energy discussions....
For those who haven't already figured this out: Dihydrogen Monoxide is a molecule with two (Di) hydrogen atoms and one (Mono) oxygen atom  =  H2O = Water.
4 - Understand the power (and misuse) of cascading assumptions
Many processes in the AE field may have 6 or 8 links in the chain. For example, the question of whether or not producing ethanol from corn actually has a useful energy payback depends on how much energy is used for: preparing the soil, planting, producing the needed fertilizer, pumping water for irrigation, harvesting and transporting the corn, grinding the corn, fermenting to produce alcohol, distilling to concentrate the alcohol and transporting the final product to the customer. Reasonable estimates for each can vary by at least a factor of 2. In this example (and in many others) -
The devil is in the details. Reality lies somewhere in between. Since the loudest voices are usually touting their own particular technology (and disparaging the competition) you often get best case scenarios for one technology compared to worst case scenarios for another. It can be hard to sort throught competing claims and get an accurate comparison of technologies.