What follows is just some analysis to get you thinking about what is the most efficient way to light your home or business. You could supplement this with specific energy calculations for your location.
Lighting Data:
Incandescent 15 lumens / Watt 750 Hours
Fluorescent 50 lumens / Watt 10,000 Hours
LED 100 lumens / Watt 50,000 Hours
First note that incandescent lights use seven times as much energy as LEDs and have to be replaced 66 times as often. Most likely the gas required for 66 trips to your local hardware store costs more than the LED replacement.
What about compact fluorescents? Compact fluorescents use twice the energy and have to be replaced five times as often as LEDs. After five replacements your cost is already about the same or more than purchasing an LED light. Now factor in the energy savings and convenience of low maintenance LEDs and you should come out ahead. Further, the LEDs don't contain mercury.
There are other factors to consider. Since LED's produce less heat they reduce air conditioning costs. Also, LEDs come with lenses that focus the light more efficiently than incandescents or fluorescents.
For a complete article on the subject please see:
LED Lights a Piece of the Energy Puzzle