I am in the process of transferring my HSA to a bank that doesn't allow me to invest the funds to a bank that does (Health Equity...side note, let me know if you have any other recommendations).
All of our investments (my 401k, wife's 401k, wife's Roth IRA, my traditional IRA) are either 100% stocks or 90% stocks/10% bonds.
I'm a little hesitant to be this aggressive an HSA, however, because those funds are there to pull in case of a health emergency.
So, I'm curious, what's your asset allocation in your HSA?