From Northern Softworks:
Lights Out is an application designed to give users more control over Apple's Energy Saver. It helps solve the problem of Energy Saver insomnia. Many software packages, scanners, and other peripherals interfere with the Mac's normal sleeping patterns. Lights Out offers a secondary idle timer to put your Mac to sleep even when Energy Saver fails to do so. The application also offers hot corners to instantly put your Mac to sleep, or keep your Mac awake. Lights Out offers the ability to customize Energy Saver settings for individual applications. This can be useful for long downloads, iTunes streams, cd or dvd playback, etc. Lights Out can even logout or shutdown your Macintosh after a specified idle period.