By default, Ubuntu requires that you login each time you run the operating system. If you are the only person using the computer and aren’t worried about security you can enable automatic login.

I think this should work for any Linux operating system using Gnome, I have tested on Debian and Ubuntu.

Well, automatic login will let you avoid to enter your login and password each time you turn on your PC, this could be insecure, but if your computer is physically secured it is Ok to enable this, that could make your booting more smooth.

How to do it?

If you are the only user on your machine and you’d like to enable automatic user login at boot time this post will outline how.

Here you can see the default login screen for Ubuntu 8.10. You simply add username and password and you have access to the Desktop. Simple, however, as you will see there are many options that can go with this login process. If you will go to System/Administration and select Login Window you will find that you have a lot of options available for login.

Fedora is one of very few distributions that does not have the auto-login feature in its graphical user management tool. Auto-login allows the system to automatically login a user without requesting authentication, that is, it enables password-less logins. While it is a very convenient feature, it is a security risk. Why?

Enabling the root account in ubuntu is rarely necessary. Almost everything you need to do as root of an Ubuntu system can be done via sudo or gksudo. If you really need a persistent root login, the best alternative is to simulate a root login shell using the following command... It is tested in ubuntu 9.10 Karmic Koala also.

If you are the only user on your Ubuntu system (or if you have a default user on a Ubuntu system that should always be the user logged in) then you might want to consider setting up auto login

The beta version of Ubuntu 9.10, which appeared last week, brought a number of much-anticipated aesthetic improvements to the desktop.  Here’s a look at the slick new login manager that users can expect when Karmic is officially released at the end of this month.

Ubuntu Tweak 0.5.4 was released today. It doesn't come with new major features except an option to customize the GDM (login screen), which you can use to change the login screen background, logo, disable the user list, disable the login sound and disable showing the restart buttons: