Maintenance 3.5 released
Maintenance, the Automator action that performs many system repair and clean-up tasks, has been updated to version 3.5. New features include:
Ability to automatically restart after Maintenance has run
Ability to automatically view the results file
Time stamp added to results file
Also, for a few versions now, Maintenance has included an AppleScript that I believe performs the same tasks for pre-Tiger 10.4 versions of Mac OS X. Included with the download is a ReadMe PDF that explains what each task is and when/why you should run them.
Maintenance is free and available from Automator World.