System Prefs: Security & Privacy: tried to enable "Automated login": But no check box available in front of "Require password .... after sleep ..." and the option "Disable automated login" was greyed out even after unlocking the system preferences with the admin password.
Solution: Disable Firevault 2 (you need to authorize by clicking on the icon in the lower left corner and type in your admin password FIRST before you can change anything). then this checkbox in front of "Require password .... after sleep ..." reappears. Then you also can uncheck the option "Disable automated login" under "For all accounts in this computer". Then "Automated login" option is enabled again in the system preferences:
Go to "Users & Groups", choose admin account, clicking on the icon in the lower left corner and type in your admin password FIRST before you can change anything, then click "Login options" and choose under "Automated login" at the top right in the pulldown menu the account that you want to log in automatically after start of Mac OS X Lion.
This ONLY works with Filefault 2 being switched OFF! Unfortunately after having turned on the Filefault 2 there is no indicator that Firefault 2 needs to be switched off again to reintroduce this "Automated login" feature.
Hope that helps.