The bookmark to login nobody but you. Simple and secure.
If you manually removed the login-dongle plugin directory, or if your version was prior to 1.4.0, some garbage is left into your database. It's harmless, but if you still want to clean it up, access the options table and remove all the rows whose option_name column start with login_dongle.
If your version was prior to 1.1.0, edit the wp-login.php file in the root
directory of your blog and remove the line that begins with