As Christians the basis of our faith is summed up in the term 'Sola Scriptura' - "by scripture alone" meaning that we base our faith solely on the Word of God as it appears in the Holy Bible. Is the bible the entire content of God's knowledge? Hardly, at best the Bible can be called "The Beginners Guide To God".
The concept of Sola Scriptura is nothing to be taken lightly, over the centuries thousands upon thousands of believers have been brutally tortured and murdered for the Bible. Keep in mind that the Inquisition was much much more than anti-semitism, the inquisition was meant to maintain control of holy scripture and keep it out of the hands of the layman. Scripture is God speaking to us, through the pens of scribes long past, long forgotten, all divinely inspired. That's why I take the sanctity of scripture so seriously, and why when deliberate attempts to putrify the Word of God like The Message, The Voice, and The Queen James come out, I get upset.
When it comes to non-canonical books the waters get a bit muddy - were they divinely inspired? Should they be part of canon? if not, can they still be used by a good Christian to learn God's will? Gnostic gospels I have no problem with... I just ignore them. Any so-called Gospel that starts out with "These are the secret sayings..." (Gospel of Thomas, Gospel of Judas) may not be blasphemy or heretical, but at best they're Midrash, AKA biblical fan fiction. But the Book of Enoch poses a problem, what is it? Is it the Word of God? It's referred to in the New Testament, so why isn't it in the Old Testament? What's the deal with Enoch?