Fluorescent lights will reduce your lighting bill by 80% 

Most energy-saving lights are compact fluorescents, this type of light bulb is commonly called a CFL.
CFLs are a great improvement on the incandescent light bulb with tungsten filament, because that filament is really nothing more that a heater in a glass bulb, the electricity is used to heat up the filament until it gets so hot that it begins glowing, that's why its called 'incandescent'.
CFLs use only one fifth of the electricity compared to an incandescent because they don't waste electricity to produce heat, another great benefit is that they will last 6 to 10 times longer than a filament bulb.
They can produce different shades of light; the most popular is 'warm white' because it most closely resembles the Colour of a tungsten filament globe.
LEDs are a relatively new technology, they consume very little electricity and are becoming popular for spotlights, reading lights and  down lights.