I love how well The Two Towers stands on its own as an ensemble adventure film as well. It's essentially the best ever within that genre, for me. The pacing is brilliant, the mixture of epic and intimate (often at the same time) is glorious, and there are just so many amazing high notes in general, all spread between interweaving narratives and locales. I will say the plotting of The Two Towers does make one mistake, though, which is that it needed to include the flashback scene from the extended edition with Faramir + Boromir + Denethor. This section of the film loses some weight and clarity without that scene, which subsequently makes that continuing plot line in The Return of the King weaker.
I believe the plotting of Fellowship of the Rings is genius, btw. It's stunning how perfectly they condensed everything down there, PARTICULARLY the opening segments of the film. It's actually very annoying in the book how Gandalf just disappears for years and years, as well as other unfocused points. Fellowship also succeeds the best of all the films in how well it introduces us to all of its characters (which includes Galadriel, even though the film messes up with her later on, since her opening voiceover at the very beginning of the film is chill-inducing), which is quite a feat with the number it has to present. The introduction to Hobbiton is also one of the most charming things ever.
Also, to be fair to Return of the King, even though it hits a lot more low points than the other films, it's still a wonderful achievement and also hits some of the biggest highs. The part at the end with Frodo saying "how do you pick up the strands of an old life" just destroys me every single time. The lighting of beacons, Pippin finding Merry on the battlefield, Eowyn's defiant triumph on the battlefield...those all come immediately to mind as being extremely impactful, and there are some others too which are at that level or close to it.
Howard Shore's music throughout all of the films is a pure Godsend.