Well, belief in God may be the most important thing to them, but my primary concern is the anti-science mentality that comes along with it. I mean, you've got nonsense like intelligent design being taught in schools, or people who refuse to get their children vaccinated because of unfounded fears of autism, or people like Sarah Palin openly mocking research on fruit flies that directly contributes to our understanding of various genetic diseases.
I'm not sure what could be done about it, but I'm concerned because I'm seeing very real consequences as a result of this way of thinking.