Do energy efficient lights really help in improving energy efficiency in homes?

I am heading toward the home remodeling and I was thinking to replace all the old lightings with the new one. My wife is suggesting me to use the energy efficient lights as they help in improving energy efficiency in home. I want to know is it really true or just a company way to sell their products? What do you think about it? Can anyone tell me if they have ever used it? Did you feel any difference in the efficiency of energy in your house?