Ok, what I am doing is making this an option on a per site basis. If you have access to your own php.ini file and you choose to use sessions, you could set it so the session id is stored in a cookie and is persistant so they won't have to log in each time. If you don't have access to your own php.ini file and you don't want your users to have to login each time then you could use cookies for the default tracking method.
