Man Looks Outside, God Looks At The Heart
Rest assured, this is not a vain attempt to promote whether or not you should or should not read the books. However as Christians it's important to have context and exercise spiritual discernment when making decisions, not just following the Christian popular majority of the day. Allow the Holy Spirit to govern your decisions, if you have the unction to stay away from the books, great do so in faith! If you do choose to read the "Harry Potter" books, again do so in faith keeping a pure and clean conscious before God. The only One who can judge the inward motives and intentions of the heart.