More on logical fallacies: Justin Weinberg adds a few more of his own to the earlier list. He also notes, "P.S. The equivocation (below) is on 'is' -- some people have trouble spotting that."

Appeal to Ignorance:
No one has been able to prove that another fallacy is better than Appeal to Ignorance, so it must be the best.

Composition:
Each of the other fallacies suck. The Fallacy of Composition is therefore better than the whole lot of them combined.

Division:
This is the best list of fallacies. It follows that there could be no better description of the Fallacy of Division than this.

Equivocation:
The best fallacy is on this list.
Equivocation is on this list.
Therefore, the best fallacy is equivocation.

The Fallacy Fallacy:
Some have argued that the Fallacy Fallacy couldn't be the best fallacy because some arguments for it being the best fallacy are themselves fallacious. Clearly, this is a fallacious argument, from which we can only conclude that the Fallacy Fallacy is indeed the best fallacy.

False Analogy:
Just as the jelly donut is the best donut, so too is False Analogy the best fallacy.

Hypostatization (personification):
Go, Hypostatization Fallacy, you can do it! If you just try hard enough you can be the best fallacy there is! Oh come on now, don't look at me like that.

Use/Mention:
If I mention the idea that "the use/mention fallacy is the best fallacy" then the use/mention fallacy is the best fallacy.