Sayyiduna Uqbah bin Amir (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him) say: "You will never recite a surah more beloved to me, nor more eloquent, than Surah al-Falaq. So if you are able not to leave it out in any prayer, then do so."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15022