While walking…

hdiutil create Private -type SPARSE -encryption -fs HFS+J -volname Private

You don’t NEED them, you may not WANT them, but if you have trouble finding what you can and cannot stick in sysctl.conf, this list may help:

This will really power off your displays, not turn to the dimmest setting:

Copy this into your favorite editor, save and run for the commandline:

Found some code snippets for OS X the other day, heres one about the iSight.