There are a limited number of power strips that purport to be "smart" available. At $25, Belkin's Conserve Smart AV is probably one of the most expensive eight-outlet power strips you’ll ever purchase, despite its popularity.
Belkin actually intended its Smart AV to be used in the entertainment room. However, it's just as relevant anywhere in the house where devices get powered up and left in a standby mode, including a den, kitchen, or bedroom.
The master outlet is the switch mechanism, and the five power outlets to the right are slaves. The two outlets to the far right stay on for devices that you don't want switched off automatically.
The way the Smart AV works is simple. Power is supplied to the master outlet. So long as amperage is above a certain value, the dependent slave outlets receive power as well. As soon as consumption on the master outlet drops below that trigger point, the associated slave outlets are switched off. Without a a reference load, we weren't able to determine the exact trigger point Belkin uses. However, after measuring the draw from several devices in standby with our power meter, we're guessing that point is somewhere between 4 and 5 W. For the strip's power-saving mechanism to function properly, your system has to have a low-power state that ducks under the trigger (and that shouldn't be a problem for most folks)