I'm going to be the contrarian here. I think Roth accounts do not create wealth. It is pay me now (US) or pay me later. Say you're in 30% tax bracket state and federal. You have 100,000 and convert. Now you have 70,000. Now in 5 years for example this money doubles to 140,000. Great, all tax free. Now if that same person decides to convert after 5 years he has doubled his money to 200,000 but after tax at 30% he is back to 140,000. So really the government is just getting their money upfront. Now you say, Yeah, but won't you be in a higher tax bracket then. Well, how would anyone no for sure. Also who says that Congress won't change their minds about this Roth deal and make it taxable?
One factor you might want to consider: the "Roth is bigger" effect if you pay the conversion from other funds:
1) Convert 100K to Roth. Pay 30K tax from other funds. In N yrs, Roth doubles to 200Kvs.
2) Leave 100K in TIRA and have 30K more in a side fund (since the Roth conversion guy spent it on taxes). In N yrs, TIRA doubles to 200K and side fund doubles to 60K . After tax, TIRA is worth 140K and side fund is worth 60K so 1) is worth more.
Then you have LOL's larger std deduction/exemption idea and who knows what tax rate changes so ...........