here's a great website written about energy and carbon issues, I found out about its english version recently ; it was written by an engineer and there a lots of articles that don't bother to be reluctant telling the truth about actual figures and orders of magnitude and rebound effect.
so here's the page that deals with the CFL lights (and talks about lot of stuff), and the stakes are not high, we're dealing with 3% of household electricity use or 1% of total energy use!
http://www.manicore.com/anglais/documentation_a/savings.html
it is symbolic, or even is a liability if you follow the official tune (keeping all parts of pseudo middle class western lifestyle intact)
(I was quite beaten to the point, didn't reload the thread
)