As an ex-Presbyterian, and calling myself a Christian Humanist, I am inclined to take exception to the way exponents of a certain brand of born-again Christianity have assumed to themselves the unique right to call themselves 'Christian'. Do they accept that the Pope is Christian or Orthodox patriarchs? Jesus rejected the hard-line legalism of the Old Testament, but many of the fundamentalist sects - especially in America - accept as if they were gospel the laws laid down in Leviticus. There was a wonderful episode of the West Wing (can't remember which series) in which President Bartlet, faced with a bunch of these bigots, quoting OT authority for their bigotry, confounded their statements by quoting other biblical sources.
By calling myself a Christian Humanist, I mean that I accept Christian ethics - see the Sermon on the Mount - although I can't accept its metaphysics.