Usually things like cableboxes aren't pleased with being turned off. The TV guide gets all wonky and takes forever to turn on. I know, I know, first world problems.
To the OP, I'd get a Kill-a-watt meter and actually see how much power they're drawing. Nothing like spending 100's of dollars to solve a 20 cents problem
http://www.amazon.com/Arbor-Scientific-P4400-Kill-Meter/dp/B001JHGY2Q Or equivalent