Comment Solved with a "smart" power strip (Score 1) 394
My power company solved this problem for me by shipping out (at no additional charge) a power strip with 1 master and several slave outlets. The TV is plugged into the master outlet, and everythign else into the slave outlets. When the TV is off, the slave outlets are automatically switched off. So regardless of whether the cable box / dvd player / name your random device would prefer to live in standby mode, it can't.
Sure, there is a 20 second delay when I turn the TV on while the box syncs itself back up with the network, but that's a small price to pay.