ilmcuts, of course, if you only need a single "per user" file, your solution is better than mine. But if you need to store many settings, then it's better to store all the "user only stuff" in a whole directory. Like I done it in my theme which is "multi-user" compliant:
http://www.litestep.net/index.php?section=2&action=details&id=83

That's why I put everything under "$DocumentsDir$Litestep\"