However If you discount the traditional IRA by the taxes that will eventually be paid on its withdrawals, yes, the conversion makes sense after a few years (4 with my numbers).
Yes, you have to do that to make a fair comparison. It's all about what you (or your beneficiaries) get to keep. If you expect your beneficiaries to inherit the accounts, you'll want to take their marginal tax rates into account into figuring the net value of the traditional IRAs.
