Question: I pay $300 a month on my credit-card balance of roughly $11,000. I have an extra $350 a month that I can use to further reduce my credit-card balance, or that I can invest in a Roth IRA. Which will give me the biggest bang for my buck? - William Scott, Spotsylvania, Virginia

Answer: The short answer is that you would almost certainly be better off using the extra dough to pay off your credit-card balance.

That said, however, this is one of those areas where the best deal in the strictest financial sense may not necessarily be the best real-world solution.

To see what I'm getting at, let's run through a scenario using the figures you've given me, and then I'll explain why you might not want to make your decision purely on the numbers.

You don't mention what interest rate you're paying on your credit card, but for argument's sake let's assume that you pay 14 percent a year, which is roughly the national average. As for the Roth IRA, let's figure that you earn 8 percent a year, not a spectacular return, but a reasonable one assuming you invest in a diversified mix of stocks and bonds.

Investing extra dollars

Let's first look at the scenario of you continuing to pay $300 a month on your credit card and then

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Citigroup's chief financial officer Gary Crittenden startled analysts on a conference call by saying the bank doesn't expect the housing industry to stabilize soon. He predicted already slumping U.S. home prices