Found on the back of our electricity bill:

enelbill

When we moved into the house in October of last year there were bare incandescent bulbs hanging from the walls. We didn’t get around to putting in low energy bulbs (CFLs) until December, when we replaced about half. At that point, our average daily electricity consumption dropped 16%. In February we replaced the rest of the incandescents and suddenly we were using 32% less electricity than when we moved in. 

Compact florescent bulbs rule: the colour of the light is excellent, they’re 3-4 times more efficient than standard bulbs, and cheaper over their life because they last so long. The only downside is that they take almost a minute to warm up to full brightness, but that’s hardly a reason not to use them. I’m looking forward to the EU following Australia’s lead and banning incandescents by 2012. Bulbs are boring, but effective in reducing emissions.

Following a tangent, I think ENEL are required to put this information on your bill by an EU directive. It was useful in this case because we’d only made one change in the whole house: light bulbs. But day to day it’s useless - the feedback is totally dislocated. As they quote in a DEFRA report on the effect of feedback on energy consumption:

…consider groceries in a hypothetical store totally without price markings,
billed via a monthly statement… How could grocery shoppers economise
under such a billing regime?

Now that we’ve changed our bulbs I honestly don’t know where else we can save a significant amount of electricity. And these numbers on the back of my bill won’t be any help.

BTW, here is some information on a Carbon Trust field trial of the effects of advanced metering on consumption (they find it reduces consumption by 10-15%).