Quoted from benheck:

This rule has been coming for a long time, was actually from Bush era!
The thing that bugs me about CFL's (and I use them everywhere) is that they're
A) Made in China (old school bulbs usually made in USA)
B) Actually create more waste when they die (transformer, mercury, circuits)
C) Don't last nearly as long as they claim to
Still, do the math:
Swap a 25 watt CFL for a 100 watt indandescent, and we can calculate with a 75 watt savings:
75 watt bulb on 8 hours a day = 0.6 kWH * 0.13 = 0.078 cents per day
Cost difference $3 a bulb / .07 cents a day = pays for itself in 38 days, the rest is gravy