I am what one would call a "frugalista", and a retired engineer
to boot.
In my mancave, in the summer, I put in the 9W CFLs to
cut down on the air condx load. In the winter I put in
100w incandescents to normalize out the load on the electric
space heater...
In the summer, the light is free, in the winter, the extra heat is
free.
I probably save 2 or 3 dollars a year. But, just the feeling that
I am taking advantages of the two technologies, makes it
something I want to do....

I am a BIG fan of LED light sources. Up to now, the cost
tradeoff doesn't make it attractive for me for house lighting.
For flashlights, camp lanterns, emergency lighting --- I am
enthusiastic about it.....
Some day, maybe not too far off, they will be mass produced in
a way to make them more cost effective..... I'll be one of the
first in line for the conversion.... but not today.