For atheists, "In God We Trust" on currency and as the official motto of the United States is one of those pick-your-battles things. It's in blatant violation of the First Amendment ("Congress shall make no law respecting an establishment of religion …"), but issues such as injury from faith healing are more important and deserve more attention.
But let's look for a moment at what we discarded to make room for this motto. E Pluribus Unum (Latin for "Out of many, one") was the de facto motto before the adoption of "In God We Trust" in 1956. That certainly showed those atheist commies which side of the theological fence we were on, but this came at a price.
One trait that is special about America is that we're composed of people who came from all over the world to pull in the same direction to make a great country.
Out of Many, One. Which country would this motto fit better than America? Out of Many, One—a custom-made inspirational reminder of who we are and where we came from.
And we flushed it down the toilet in favor of "In God We Trust," a one-size-fits-all poncho that could be worn by a hundred countries.