Don't Say 'Holy Quran'
Holy in the arabic language is (transiteration) 'Muqaddas' , And Allaah ta'Alaa has never refered to the Quran as being, Quran-il-Muqaddas, nor will you find in the reliable books of Sunnah Qurana-il-Muqaddas (The Holy Quran). Allaah called the Quran, Quran-il Kareem(Noble Quran), Quran-il Hakeem (The Wise Quran), Quran-il Majid (The Glorious Quran)etc. So in-shaa'Allaah lets refer the Qurran according to the names Allaah had given it, not simply imitating the christians without intending to do so. And Allaah ta'Ala knows best.