Just stumbled across a nice little function of Moodle 2.3 that I don't want to forget about.
If you have a file that regularly updates and is used in more than one course, you can now keep in in your Private files and add a link to it in the course pages.
This way, you can update your Private Files and not worry about updating all your courses separately.
There are still problems with the Private Files, sadly. I really want people to be able to message each other and attach files in the Private Files area to the message. It would also be great if you could edit a file and save it directly into the Private Files area instead of downloading a copy, saving it locally, editing and uploading the edited document to Private Files.
This may be possible, but I've looked, and I don't think it is. It's just one of those things that seems so obvious to me that I assume it's there, but does not seem to be.