There's too many to name, but I chose one from Sakurasou no Pet na Kanojo. I've literally been advertising this anime, it's in like half of my 回答 on here.
Hmm.... while my actual お気に入り moment is the ending to FullMetal Alchemist: Brotherhood, it's kinda spoilerish (it's the ending. duh.) So, my 秒 お気に入り moment in all of anime: