My order of operations for the bulk of extra income.
1. Max out 401k and Roth
2. Max out HSA
3. Max out 529
4. Pay off house
5. Taxable investments (once house is paid off)
If I were young again, I would get as much low interest credit I could and do something like 70% DGRO, 30% MUB in my taxable and 60% DGRO, 20% FREL, 20% TLT in tax sheltered. I have learned that my maximum risk tolerance is about a 30% total draw down before I start to freak out and do something irrational, hence the bonds. My portfolio choices keep up with the S&P but have much lower draw-downs in both 2002 and 2008 when I did some stupid emotional stuff with my portfolio.
For paying off the house in a lump sum after you have been saving ahwile... If you have a tendency to blow money when you see a bunch of it sitting idle or the economy tanks, paying off the house locks it up so you cannot easily get at it. I have learned that making withdrawals as hard as possible has probably been the best investment decisions I have made over the years and has the highest returns. Protect your investments from yourself first, then worry about the other things. Fidelity research says that dead people and people who forgot their password had the best returns...