I got one of the "classic" one's as part of my Eon energy plan.
Makes you think about leaving that light on (as well as scaring the poo out of you when the kettle, microwave, washing machine and iron are all on at the same time
).
It has made me change the way I do things in that I now turn the kitchen light off when I'm not in there and things like that but not much else really as I never leave the TV on standby etc.