This is one of my favorites: a religion map. The data for Canada is from the 2001 Census, so it might be a bit old, but not too much. The data for the US is the most recent ARDA data with some adjustments I made: I took the adherents data and compared it to the ARIS survey of religious self-identification. I found that the data matched up nationally for Catholics and minor religions but not Protestants due to the about 14% of the population that identifies as generically Christian but doesn't attend any one specific church. So I adjusted for these "invisible Christians" to ARIS levels, and divided the new total adherents by the total adult population and fixed a couple other minor issues to get this map:
It's worth pointing out that "no religion" does not necessarily equal atheist or agnostic.
Surprised that Romney won more "no religion" counties, 19-15 (didn't check Alaska).
