It doesn't make sense to convert now, pay a higher tax on all that income now, just to most likely be in a lower tax bracket in retirement.  With only the knowledge of you being in a higher tax bracket now, I would let the IRA ride until retirement.  Then move it over to a ROTH systematically, not all at once, unless it's a small amount.  

Convert as much as possible to bring your taxable income upto, but not into the next higher tax bracket.