If you are the only user that is using the desktop and you do not have any sensitive information, you sometimes might find it is troublesome to go through the login windows and key in password after every boot up.

Here is how you enable auto login feature in Ubuntu.
On Taskbar choose System > Administration > Login Window

Then in Login Windows Preferences highlight the Security tab. Just check Enable Automatic Login with your preference user selected and you have get rid with your Login Window already.