Several years ago we received from our power company coupons that allowed us to purchase the fluorescent lights very cheaply. We used them exclusively for a couple of years and did see a savings in the energy department. Then for some unknown reason they got swapped out for regular, and we noticed a difference in our bill. I am not sure when, how or why they got switched out, but we have since switched them back. I know that they do help and I cannot wait to see the savings again.
As a side note one of the benefits of children growing up and leaving home for college is that the mysterious individual named "not me" seems to go with them. I suspect that character "not me" was the culprit in this case! :)