Depending on how many variables/data you're looking to save the app.config/settings file can be the ideal place.
Check out the Settings Tab in the Project properties and note that you can set both Application settings and User settings. Application settings affect the entire application. User settings are stored per user.
The section of the app.config that contains user settings will be saved to the user directory when they are saved and reincorporated when they restart the app.
Check this url for an introduction to Application/user settings on MSDN and also this SO url for a similiar question.:
You could also look into storing your familiar old .ini files in a per user .ini by checking out the Special Folders enum as per this url.