Q. There are two type of dhikr during Eid days:
1. Allahu Akbar (3x) La ilaha Ilallah, wa Allahu Akbar, Allahu Akbar wa lillahil hamd
2. Allohu Akbar (2x) La ilaha Ilallah, wa Allahu Akbar, Allahu Akbar wa lillahil hamd
Which one is valid according to sunnah ?

A. Both are valid according to Sunna, but Hanafis and Hanbalis prefer a double repetition, while Shafi`is and Malikis prefer a triple one. (For Shafi`is see Nawawi's remarks in al-Adhkar, chapter on the dhikr prescribed by the Law in the two `Eids.) There is no specification about it in the hadith, but the triple repetition: allahu akbar allahu akbar allahu akbar was the practice of five of the major Companions, see Shawkani's references in Nayl al-awtar. wallahu a`lam.