I'll first start off by saying that this episode is completely standalone. The episode isn't even shot in the perspective of the 10th Doctor. That being said, it's a fan favorite and the Weeping Angels are the biggest reason why. If there's a standalone episode that you absolutely cannot miss, it is this one. The Weeping Angels do make reappearances later on in the series, but this particular episode is a lot of fun to watch. The tension in the atmosphere is all too palpable and you'll swear after watching it in the dark for the first time, that there is a Weeping Angel right behind you.