He currently makes about 41,000 and I will make 45,000 - 50,000 this year (commission, hard to tell), so I believe that puts us in the 15% tax bracket.
Correct. After taking the standard deduction and exemptions your taxable income is <$74.9K so you are in the 15% federal bracket.
Does a Roth make more sense since he may still have income after I retire?
If you do withdraw (as forummm notes, this is your choice) while one is still working for wages similar to what you have now, you will still be in the 15% bracket. In that case, the simple math says "no difference between traditional and Roth" - but the greater flexibility of the Roth should tip the scales in that direction for you.
If you wait to withdraw until neither of you is working, and if you have no SS and no pension, then some of the withdrawals will come in the 0% and 10% brackets and traditional will have been better. Any withdrawals that push your taxable income into the 15% bracket would be better (as discussed above) in Roth.
If you do have SS, depending on how much you withdraw your marginal rate can get >25% due to the way SS is taxed so this is not a simple question to answer....
I considered splitting between a Roth and traditional but understand there may be 2 sets of fees for 2 accounts.
As nereo noted, in general with Vanguard this is not a concern. You may get a slight break on fees by having all in one Admiral-class fund instead of 2 Investor-class funds, but the difference will be minimal.
(see case study - always moving forward)
http://forum.mrmoneymustache.com/ask-a-mustachian/case-study-always-moving-forward/And one other note: given current tax law (i.e., no federal tax on LTCG and qualified dividends if you are in the 15% federal bracket), and assuming your investments don't ever grow enough to put you in the 25% ordinary bracket thus incurring 15% federal tax on LTCG and qualified dividends, and assuming
no state/local income tax - you are better (at least, no worse) to put everything in taxable accounts. But if you are paying state/local income tax (and they treat LTCG+QD as ordinary income) then Roth is still better. See the '401k vs Taxable' tab in the case study
spreadsheet if interested.