Is Halloween too pagan for Christians? I have no opinion about whether or not anyone else's family should celebrate the day (growing up, my family did not) but I do recommend a fascinating look the holiday's origins.
Pastor Abrahamson points out the surprisingly modern sources of "pagan" Halloween elements and challenges us not to believe everything that that Wiccans and Neopagans claim (Halloween doesn't actually have a valid pagan history, much as they would like to believe that it does). He also encourages Christians not to abandon celebrating significant days in the Church Year.
Read his article, "Redeeming Holy Days from Pagan Lies — Hallowe’en: A short history," by Pastor Joseph Abrahamson