Death Note eps 16-27
The way they handled the "new Kira" storyline was far more inventive than I expected. Really felt like they were bringing the series up to the boil at exactly the right time, for a real barnstorming finish. And that's what it would have had... if it had actually finished at the end of its second cour. I wasn't actually 100% happy with how they brought about the event in episode 25 (imo L is somewhat clutching at straws by wanting so desperately to test the "13 day" rule. He has no logical reason to believe the other rules but mistrust that one, except that he is so anxious for his one working theory to be correct), but apart from that small detail everything was way above my expectations. I don't think the series could have had a more spectacular and fulfilling ending. In comparison, L's successors have all the feelings of a standard shounen need-to-extend-series-so-just-repeat-stuff-you've-done-before scenario, and I'm not looking forward to this last cour so much.
Also, the OTT fujoshi pandering in ep 25 was so out of character for the show that it was a little offputting. On one hand I half want to think that there are lots of examples of this with female characters in other shows that I just brush off as acceptable entertainment, on the other hand this felt like it was on a different level than that, due to the randomness.