4
I think he wants a site that doesn't show a login block but still allow the admin user. Like was said just turn the login block off (visible off) so it never shows. Than you manually enter /user.php to login when needed. You can make a link on your page, header, footer etc to allow an easy login method for those times and users that do need it and still keep the space minimal.
This is also handy for public sites that have no need for user login except for content management by the admin and designated users.
