Either way, it's going to be a huge tax bite. And that brings me back to the two questions at the start of this column. Taxes: now or later: If you believe tax rates are headed up, it might be tempting to do the conversion next year, unless top personal tax rates are increased even before then. Remember, when Kennedy became president, the top personal tax rate was 91%! But how will you feel about writing that huge check to the government next year? What better things might you have done with that money you're sending to the government to pay the conversion tax? (By the way, don't take the money out of your IRA to pay the tax bill -- or you'll lose the best part of that benefit -- future tax-deferred growth. And definitely don't do that if you're under age 59 1/2 or it will be treated as a penalty withdrawal.) The one group that might benefit most from this conversion opportunity are younger savers. They'll have more time for the money to compound, and overcome the taxes paid now. Then all that money would come out tax-free at retirement. And for those who have lots of money, there is an additional benefit to converting to a Roth. Not only are there no required minimum withdrawals from a Roth (at age 70 1/2), but if you don't spend the money in your lifetime, your heirs can allow it to continue to grow tax-free, or withdraw it tax free, unlike withdrawals by beneficiaries of a traditional IRA .