Noticed an article today on Skeptical Christian titled "Arguments Christians Should Not Use". It's a good article, so take a look. I'll comment briefly on each 'bad argument' raised in that article here:

Pascal's Wager: Certain forms of Pascal's argument may be worthwhile, but I've found that generally speaking they are not considered very persuasive.

{Bad person} was an Atheist, or {Good person} was a Christian: The obvious comeback is "{Bad person} was a Christian" or "{Good person} was an atheist".

Everyone Believes that God Exists: If taken literally, this seems to be refuted easily by considering that there are approximately 1 billion "nonreligious" people in the world, if you go with Adherents.com's numbers. The less literal version, that "most" people believe God exists, proves nothing about the truthfulness of the proposition, and as Skeptical Christian points out it is an argument ad populum.

You Can’t Know that God Doesn’t Exist Unless You’re Omniscient: This argument is actually true; however, most atheists realize this and argue only that there is sufficient evidence that God doesn't exist. Or the reverse, that while there is some positive evidence that God exists, the evidence is not significant enough for them. In this way, the argument as formulated above is attacking a straw man. I disagree with the atheist assessment of the evidence, of course.

You Just Have to Have Faith: Oh no. Not only is this not an argument, it smacks of "blind faith" which is a big turn off for most non-Christians. The problem is that Muslims, Mormons, Raelians and all other religious groups could say the same thing.

Atheists Have no Morals: Obviously this is untrue, most/many atheists behave morally. The distinction needs to be made, as I alluded to in my previous post "Hope vs Unyielding Despair", and as Skeptical Christian also notes, that there is no objective foundation for atheist morals.

Turn or BURN!: aka "You're going to hell!" This is an ineffective argument because it is so emotionally offensive to people that upon hearing it most people will just shut you right off. Also, Christians should be at least wary of judging others, as per for example Matthew 7:1!

Of course, there is no reason to use such 'bad arguments' when there are so many good arguments available for the Christian faith. (See any of the sites listed in the "Links" in the sidebar.)