Yes. Such a turn on.
I wouldn't ever go out with someone who has different religious beliefs to me because it's just asking for arguments.
I doubt they would get along, Christians always preach and Atheists always say god is nonexistent. If Christians could stay away from the "I am going to change you" idea then maybe.
As an Atheist I would not go with anyone from any religion. We don't and no doubt will not have the same beliefs which will just cause tension in the relationship from within and without.