For my site I like to include two separate user interfaces, one for my public visitors, and another for those who are logged in. I plan to have a few differences in the layout, like a different header and a few different positions that may contain tool-bars and certain options. Obviously I have to use a check against whether a user is logged in or not, but how to load separate templates under those conditions I am not so sure the best approach.
(If there is a better approach please let me know, maybe I can keep the same layout but load only certain blocks whether a user logged in or not, but this seems more complicated to me.)