The Downtown Elgin blog had a post (read it) about the street light program. It reminded me of a web page I came across one time: The Cost of Light Pollution. Here's what it says:

Assuming that the city uses regular cobra-head design lamps, the loss would be "only" 30% = 100,620$ /year. Lost, in vane, for nothing, to illuminate the birds and airplanes. To wash the stars out of the sky... Paid by for the citizens of Elgin, Il.

I don't know if his numbers are correct but they're worth thinking about. I'm not much of an astronomer but I sure do like it when I look up and see Orion.