With all the uncertainty surrounding Roth conversions, there is one variable that is almost guaranteed:  once you pay that tax on the conversion (or salary), you won't ever be getting it back.  NOLs are a wonderful thing - sort of - but they're rarely available to most taxpayers.  And, in the days when we actually had interest rates, I'd much prefer earnings or appreciation on $10 than on $5.  Further, medical costs and nursing home costs have a funny way of approximating those RMDs, potentially reducing or eliminating their tax bite altogether (better yet, providing conversion opportunities to leave the remainder to the kids).  While I'm not a fan of the estate tax and would prefer a reduced RMD, I'd certainly rather be diversified (from a tax standpoint) having seen enough to know that the odds aren't always in your favor, or the future as predictable as some might lead you to believe.