Is your employer maxing your HSA?
If you have an HDHP (which you must have if you have an HSA), your #2 priority should be maxing the HSA, as it has all of the advantages of a ROTH IRA and a traditional IRA.
Here's how I would prioritize
#1 401k up to employee match
#2 HSA
#3 Taxable accounts if you don't have enough for an emergency. Also, you sound like you are in the 15% marginal tax bracket. You realize that capital gains at that level are 0%, right? It's basically like having a roth account for all of the gains that qualify (if you have a gross adjusted income of 65k, and the marginal tax bracket is 72k, you can sell stocks/funds with up to 7k of capital gains and pay no taxes on them).
#4 Roth IRA for you and your wife (so 11,000 per year) as long as you are in the 15% bracket.
#5 Taxable, Extra Mortgage, 401k --> I don't think any of these stands head and shoulders above the other if you are in the 15% bracket and your mortgage is 4.25%. If you are in a state with a high state income tax now but won't be in retirement, that's a point for the 401k. If you want flexible money for early retirement, that's a point for taxable. If there are significant tax bonuses for paying more for your mortgage, could be point for that.