A paper by two psychologist trial consultants with a mind toward ensuring good jury selection:
Contempt for out-groups— those members of society that are identified as "not like me"— is as old as time. But for all the awareness of bias, hate crimes, and prejudice against minorities, some get overlooked. Atheists are the most mistrusted, reviled, and disliked minority in the United States, according to numerous studies. Jews, African Americans, homosexuals, illegal immigrants, and even the much-mistrusted Muslim communities are all held in higher regard by the average American than are Atheists. The threat of spiritual alienation is more compelling than anything other than immediate injury.
The full article is well worth a read.