Consistency in the Practice of Religion
Many people argue that Islam is a religion different than any other in terms of its political and worldly aspirations. In my opinion this is not true. While there may be some secondary or tertiary level differences between religions in this regard, the primary danger and commonality of all monotheistic creeds are the reliance on faith and the attributing of the Good to whatever some ineffable being decrees. Those set the method and goal, and eventually dictate that believers attempt to enact the God's will on Earth. Everything else is details.
That said, there is a marked difference between modern day Christians and Muslims. The majority of the latter take their religion seriously and practice it consistently, while the majority of the former hold a contradictory sets of views: faith mixed with its antithesis, reason (a respect for which marked the glorious Enlightenment).
Unfortunately, as the Enlightenment fades further from the scene, Christians are beginning to practice the more unadulterated version of their religion, with predictable results. See for instance the literal 6,000-years-since-Creation-believing evangelicals. Or the prominent public comments on rape and abortion by various Republican candidates. Or the recent blasphemy ruling in Poland.
Expect a continued devolution to a consistent faith-based practice of Christianity if no one rises to ably defend a secular, pro-reason worldview. (Obviously I think Ayn Rand has given us one and admirably defended it, but it remains to be seen if enough voices will emerge to use her ideas to substantially influence the culture.)