Check in the Third Party Plugins forum for my Settings Saving Script. If you set this to run the "load savings" script on login and "save settings" on logout (for all the users on the system) you can automate this process and still be able to change settings from within any user account. If you have a specific user account that you want to prevent from being able to save persistent settings, simply don't have that user account run the "save settings" script. This will allow them to change settings as they wish inside MC, but when they logout and login again it'll replace any changes they made with the original settings.
I should note... You apply login/logout scripts through the Group Policy Editor in Windows XP Pro. I don't think you can do it with XP Home (and I don't know the deal with all the various versions of Vista at all). If you're running Home, the best you can do is get it all set manually how you want, and then run the Save Settings script. Then, add the Load Settings script to the Startup folder of of your Start Menu (either your own or All Users depending on what you want).
EDIT: I didn't realize it before when I wrote the above, but I never actually built a Load Settings companion script (since you can just double-click on the REG file to load it manually). I'll try to get to this when I get back from my conference. If you know anything about the Windows Scripting Host you might be able to figure it out yourself (it's pretty easy). I have one of these setups myself at home, but I used old BAT files (which are less elegant and popup a black command window briefly when they run). I've never gotten around to fixing it...