For those that are irritated by Ubuntu's decision to have users names show at login there is a fix. Read on...
How to Remove (Hide) Users list at login Screen in Ubuntu 9.10 (Karmic)
source: http://www.ubuntugeek.com/how-to-remove-hide-users-list-at-login-screen-in-ubuntu-9-10-karmic.html
One of the new features in Ubuntu 9.10 is it show the currently available users list at login screen if you want to hide this just follow one of the following method
Method 1
Open the terminal and enter the following comamnd
sudo gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --type Boolean --set /apps/gdm/simple-greeter/disable_user_list True
Method 2
1. Logout of your current session and return to the GDM
2. Switch to the tty command line prompt using Ctrl-Alt-F1
3. Login using your normal login/password
4. at the command line prompt type: export DISPLAY=:0.0
5. then type: sudo -u gdm gconf-editor
6. Switch back to the gdm screen using ALT-F7
7. Then navigate to /apps/gdm/simple-greeter and tick disable user list
8. Restart gdm
sudo /etc/init.d/gdm restart





