Is changing your light bulbs a waste of time?

I think so.
At the moment China is opening a new power station every six weeks. They plan to build 45 new airports in the next 5 years. The city of Bejing has had more construction in the last 12 months than Continental Europe has constructed in the last 3 years. I have no qualms about saving energy but don't think your low energy light bulbs are going to make the difference.