Every year at the holidays, we set our shopping sights on the newest, the latest, the trendiest. But if you’ve got a video buff on your list, you’ll find that many of this season’s DVD picks are about looking back, about holding onto yesterday, or yesteryear. Sweeping studio-vault surveys, sign-off collections of Batflicks and Harry Potter movies, toasts to “Friends” and “Entourage” . . . the list goes on. (As one fondly remembered reissue might kinda-sorta melodiously put it, “Those were the daaays.”) We offer some titles to consider.