I assume the plug you are referring to is the "powerdown" plug which can be bought for just £3.00 from here.
If so, we have a few to distribute if you would like to try one.
The version we have (although there may be other types which do different things) basically act as a 3-way plug adaptor (i.e. you plug your TV, DVD player, lamp and other such items into them) and they then completely "power down" all items connected to the plugs when you use your normal TV remote control to switch the plug off. It therefore avoids the energy used from standby.
The version we have also has a socket which does not power down when the remote control is used, so you can plug in items that need to stay on (i.e. some set top boxes).
The main drawback is that you end up using your remote control entirely to switch the items off. You therefore become conditioned to this which runs the risk that you won't physically switch items off (e.g. other TVs in your house) which don't have a powerdown plug attached.
The other "drawback" is that most modern TVs use very low energy on standby, so the benefits are marginal. It would be much more effective in terms of carbon and cost savings to ensure your lights and heating are switched off at appropriate times.
In saying that, some so called "techno fixes" can be really useful. Automatic flush and light controls in offices for example.
Anyway, just let me know if you would like one to try.