We can certainly save a bunch of energy and money using modern light bulbs.
They are uniformly more efficient than the old incandescent bulbs.
And--in theory, anyway--they last long enough to cover the addition upfront expense of buying them.
But the compact fluorescent bulbs (CFL) contain some toxic substances that require more attention to disposal.
We get the word on CFL bulb recycling, and a general refresher course in where things go, from Denise Barnes at Rogue Disposal & Recycling.