Today's New York Times has an article on how much energy is used by electronics devices that are left on vs. putting to sleep or turning off. Even if you choose to leave your audio components on 24/7, you may want to look at your practices with computer monitors, cpus, dvrs, and cable boxes. Here is the link:
http://www.nytimes.com/2007/06/14/technology/14basics.html?_r=1&ref=technology&oref=slogin
http://www.nytimes.com/2007/06/14/technology/14basics.html?_r=1&ref=technology&oref=slogin