Best episode? Hmmm... can't really choose between Twilight's Kingdom, Keep Calm and Flutter On, Luna Eclipsed, Mysterious Mare Do Well, Power Ponies, Read It and Weep, A Friend in Deed, Apple Family Reunion, and Sleepless in Ponyville. However, I'd like to say I really, really enjoyed Family Appreciation Day. Mature lesson, very fun and interesting story, and quite a bit of character advacement. This is a highly unappreciated episode.
Or maybe I'm just a sucker for sentimentality.
Yeah, no kidding. Don'tcha just love it when the only time the writers make Fluttershy actually realistically dislikable in aspects of characterization is when she's completely out character herself to her element and general personality?