For the Christians who treat atheists as baby-eating satanists, here's a video for you. An America without atheists would be a dreary place indeed, as the comparisons with other countries with virtually no atheists illustrates.
And no, no one would consider the information in this video as solid science suggesting we'd be better off with an atheist-only nation. If evolution teaches us anything, it is that homogeneity is a dangerous survival technique for a species. Best to have a variety of traits and viewpoints, for no one knows for sure what the future holds.