The BBC News website has an article "Lighting the key to energy saving" that quotes the IEA as saying a global switch to efficient lighting systems would trim the world's electricity bill by nearly one-tenth. Better building regulations would boost uptake of efficient lighting, it says. Nineteen percent of global electricity generation is taken for lighting - that's more than is produced by hydro or nuclear stations, and about the same that's produced from natural gas.
There is a strong case for introducing lighting measures into building codes. Currently codes have a lot of energy measures in them, but with few exceptions there aren't specific provisions for lighting.
A related article argues for banning the incandescent light bulb, which includes this quote: "They waste so much energy that if they were invented today, it is highly unlikely they would be allowed onto the market."
The Energy Blog has strongly argued for more energy efficient lighting since being enlightened while researching the post: "Wal-Mart's Bright Idea"