Separation of Church and State

I run the risk of being labled by admitting to the following thoughts. I am clearly aware of the undertones that are becoming more overt by the year. These overt undertones could be a reaction to Christianity's often holier than thou mentality, but never-the-less, I find the rejection of all things related in anyway to Christianity a bit pig-headed and just as judgemental as the holier than thous.
As I am navigating through my first year as an English teacher, recognizing the lack of texts to choose from, I began looking into new British novels to teach to the seniors. One such book, a somewhat steamy and mysterious novel concerning an Anglican priest came to mind. But I was immediately choked by that question of appropriateness, not so much because of the sex, but because the religious theme is quite prevalent.
I then thought of C.S. Lewis, by far one of the most renowned British authors of the modern era. He was clearly a Christian apologetic, interspersing some less relgious writings throughout his career. But his best work is by far christian. So, I am hesitating at introducing my students to a wonderful author simply because he is christian. Ironic isn't it? That those who discredit Christianity as exclusive and narrow-minded, do just that whenever it comes to Christian thought. It reminds me of that whole elementary school birthday invitation thing. You forgot to invite me, so I'll forget to invite you--and make sure you and everyone else knows I forgot to invite you.