This is a good question and varies based on your specific needs, which, by the way will change as you accumulate money into your HSA account. 

If you would like to start a discussion on this topic, we invite you to start a thread on the HSAeducator Forum, you can click here to get there and start a conversation based on your own needs.  You will need to register on this site to participate, but it only takes a few seconds, and you are already here.

As an alternative, if you want to read another thread on the topic(in the spirit of Miracle on 34th Street, we found a pretty good discussion going on at bogleheads that you might want to have a look at as it may address some of your questions and help sort things out for you.   We are all about HSA education, so when we find good stuff out there that might help you out, we want to do all we can to help you make informed decisions. 

P.S.  If you want to get in the Holiday Healthcare Spirit, please be sure to read "How The Pinch Stole Healthcare"