I just got a couple of new LED shop lights to replace the old F40 T12s
that were cranky and did not like to start.

The savings in power is significant if you had a lot of them.
The LED is about 20 watts, the F40s are almost 110 watts.
(19% of the power used for more light)
It works out to 1.2 cents an hour per fixture Payback is somewhere
around 3333 hours, minus whatever I spent on lamps.
8 hours a day for 416 days.

http://gfretwell.com/electrical/LED%20shop%20light.jpg

I think it is a deal.