During our working life my wife and I both funded our retirement plan options to the max. When I ER'd the 401k and company deferred retirement money was rolled over to an IRA. Now we have much more money in IRA's and Roth's then taxable savings. This gives us a nice low tax profile. We can make changes to our investment accounts without worrying about taxable gains until withdrawal.
I've converted the max amount to Roth's each year. Probably won't start taking SS for another 6 years. This coming year I won't convert to Roth's since in 2008-2010 the cap gain rate is zero up to the top of the 15% bracket (see this http://www.early-retirement.org/foru...-me-31953.html
I think this will work out over the next 10 years which is what counts for me. Who knows what may happen in the next 20 to 30 years though as far as tax law is concerned.