Just for the hell of it, I'll post some common examles based on this site. kenzomatic said:
From - Seventh edition, Elements of Argument,
by Annette T. Rottenberg
Common fallacies
1. Hasty Generalization
Drawing conclusions on the basis of insufficient evidence. Many of our prejudices are a result of hasty generalization. A prejudice is literally a judgment made before all the facts are in. The Wii and Xbox have the same processor speeds, and only slightly more memory. Therefore the Wii is barely stronger than the Xbox.
2. Faulty Use of Authority
The attempt to bolster claims by citing the opinions of experts. Too many times to think of just one.
3. Post Hoc or Doubtful Cause
Latin - post hoc, ergo propter hoc, meaning “after this, therefore because of this”. The arguer infers that because one event follows another event, the first event must be the cause of the second. The PS3 has a Blu-Ray player. HD DVD was discontinued. Therefore the PS3 is the reason HD DVD was discontinued.
4. False Analogy
Many analogies are merely descriptive and offer no proof of the connection between the two things being compared. That's not something I've ran across here a lot, but I hear movie critics put down some movies this way. Say a Michael Bay movie ist just to have fun for a couple hours, the critic would say that drinking until you puke is fun for a couple hours, but you still have a hangover. 
5. Ad Hominem
The Latin term ad hominem means “against the man” and refers to an attack on the person rather than on the argument or the issue. Too many times to think of just one.
6. False Dilemma
As the name tells us, the false dilemma, sometimes called the black-white fallacy, poses an either-or situation. The arguer suggest that only two alternatives exist, although there may be other explanations of or solutions to the problem under discussion. If you think the Wii can get away with not having the most processing power, you must want us all to still play with Atari graphics.
7. Slippery Slope
If an arguer predicts that taking a first step will lead inevitably to a second, usually undesirable step, he or she must provide evidence that this will happen. Otherwise, the arguer is guilty of a slippery slope fallacy. You get this on reasons for and against using Blu-Ray this gen.
8. Begging the Question
If the writer makes a statement that assumes that the very question being argued has already been proved, the writer is guilty of begging the question. Why do you support the Wii ruining gaming with its kiddie crap?
9. Straw Man
The straw-man fallacy consists of an attack on a view similar to but not the same as the one your opponent holds. It is a familiar diversionary tactic. See the Wii and Atari graphics.
10. Two wrongs make a Right
The two-wrongs-make-a-right fallacy is another example of the way in which attention may be diverted from the question at issue. Can't think of any right now.
11. Non Sequitur
The Latin term non sequitur, which means “it does not follow,” is another fallacy of irrelevance. In a non sequitur, the conclusion can be either true or false, but the argument is a fallacy because the conclusion does not follow from the premise.
Kenzo summery from book - Ex. Rich people are more suited for president. There is no need to buy a game if you can pirate it (from the same people who bemoan the loss of the Dreamcast). 12. Ad Populum
Arguers guilty of the ad populum fallacy make an appeal to prejudices of the people. They assume that their claim can be adequately defended without further support if they emphasize a belief or attitude that the audience shares with them. Using the sales of a system in a context other than potential sales of a game on that system.
13. Appeal to Tradition
In making an appeal to tradition, the arguer assumes that what has existed for along time and has therefore become a tradition should continue to exist because it is a tradition. Game X has always been on System Y, or at least the last couple gens. Therefore, you CAN'T put it on System Z! 14. Faulty Emotional Appeals
In some discussions of fallacies, appeals to the emotions of the audience are treated as illegitimate or “counterfeit proofs” All such appeals however, are not illegitimate. Not exactly done on boards, since everyone here is part of the discussion, and not the audience. | 
