Which is the greatest verse mentioned in the Holy Qur'an?

The verse in question is the Verse of the Throne (Ayat al-Kursi): "Allah - there is no deity except Him, the Ever-Living, the Sustainer of [all] existence. Neither drowsiness overtakes Him nor sleep. To Him belongs whatever is in the heavens and whatever is on the earth. Who is it that can intercede with Him except by His permission? He knows what is [presently] before them and what will be after them, and they encompass not a thing of His knowledge except for what He wills. His Kursi extends over the heavens and the earth, and their preservation tires Him not. And He is the Most High, the Most Great." The proof for this is the hadith of Ubayy ibn Ka'b, where the Prophet, peace and blessings be upon him, asked him: "Do you know which verse in the Book of Allah is the greatest?" He replied: "Allah - there is no deity except Him, the Ever-Living, the Sustainer of [all] existence." The Prophet, peace and blessings be upon him, then struck him on the chest and said: "By Allah, may knowledge be pleasing to you, O Abu al-Mundhir."