Comment 28 for bug 445123

Change the above to :

sudo gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --type boolean --set /apps/gdm/simple-greeter/disable_user_list true

never cut&paste then modify someone elses command >.<

Doing it this way will force you to still use a login/password arrangement but the username dialogue box will only appear after clicking 'log in'