Power conditioning has long been an assumed requirement for the best audio-video systems. And there's no shortage of manufacturers lining up to supply the perceived need. Need line filtering, surge and spike protection, and multiple outlets? Ding! There are dozens of choices, some more effective than others. Need a device that will not only clean up your power line, but also maintain 120 volts when your power company is straining to keep up with demand? Ding! The field narrows, but there are products out there that will do that, too. Need battery backup in case of a partial or complete power failure? Bzzzt! Wrong question. Until recently, you'd have to look for that in the computer department of you're nearby electronics supermarket.