Turn Down the Lights
The above map strikes me as an issue of aesthetics, but that might be because I grew up in an area with minimal light pollution (thank you, rural Nebraska.) As Mother Jones points out, an overlit America is a less healthy America:
A recent American Medical Association report (pdf) concludes that the disrupting effects of nighttime lighting on our bodies' circadian rhythms may contribute to "obesity, diabetes, depression and mood disorders, and reproductive problems." Moreover, artificial light causes our bodies to suppress the release of melatonin, elevating our risk of contracting cancer, and especially breast cancer.
Even worse: "Eight in ten kids born in the US today will never see the Milky Way."