It depends on what your choices are. Sometimes Roth is better, but it depends on what the other option is.
contributions to traditional IRA would be best because it would lower your taxes while in a high tax bracket. This is not a choice for you (too much income and covered by 401k). I don't think it is a choice for her, but you should check. The phase out is different for her since she is not covered by a plan at work
2) Roth IRA would be your next best choice, but I think (not positive) there is too much income for either of you to be eligible to make direct contributions.
3) That leaves three possible choices - note that all these choices deal with money that is going to be taxed anyway
- non-deductible contributions to tIRA - poor choice in my opinion
- taxable account - better choice because the earnings will be taxed at a lower rate than in an IRA
- back door contribution to Roth IRA - probably the best choice because the earnings will not be taxed at all.
However for that last choice - it is only good if there are no other tIRA, SEP IRA, or SIMPLE IRAs to complicate the matter. And we don't know if you have or is she has any of these other IRAs.