This is one that sometimes slips past us if we are not looking for it:
Amphiboly: (syntactical ambiguity) a fallacy of deliberately misusing implications. We see this used a lot in TV advertizing. Example: "9 out of 10 medical professionals recommend our pain reliever." This assumes that all medical people are experts on pain relief, and that 90% of all of them make such recommendations. The Watchtower falls victim to (or uses) this type fallacy. What the consumer is not told is that the "9 of 10" could be in-house medical sponsors, and the total number could be 10, but that it bears no relevance to the entire community of doctors.
I like this example too :
Two Wrongs make a Right: (Similar in style to Ad Hominem) This fallacy is committed when we attempt to justify a wrong action by charges of a similar wrong. The assumption is that if others do it, then why can't we do it too. In the Ad Hominem style, we attack the person to justify our actions, as if to say, if you have done bad things, then who are you to point out my weaknesses.) Example: Supporters of apartheid in one country will justify their system by pointing to past practices of slavery in the United States. Another Example: "How can you charge the Watchtower Society with bad child abuse policies when it is far worse in Christendom, especially the Catholic Church.