Changing the SQL Server service account - any additional considerations?

I have inherited a few instances that are running under LocalSystem. I need to change this to a domain account as we are changing our backup strategy to go to a network share and then to tape and I need to be able to assign permissions. I know that the recommended way to change the service account is to use SQL Server Configuration Manager. However, is there anything else I need to be cognizant of? How can I be sure that directory permissions will suffice for the new service account? Will Configuration Manager assign proper permissions to folders that contain the data/log/binaries, regardless of where they are?