I would have to agree with
Ainaserkewen.
This is not to say that TTT and ROTK are not great movies; it's just that FOTR was the best of the three. I own all three in EE DVD format, and on any given night could watch any of them. Most times I choose FOTR as (to me) it was the movie closest to JRRT.
TTT was too PJ, and though he corrected this somewhat in ROTK, it also smelled more of PJ than JRRT.
To me PJ saw how well FOTR was received and thought that this permitted him to (a) add more of his own material to TTT and (b) hype it up a bit with more special effects. After TTT, he did the same in ROTK, but also must have heard some of the grumblings from the faithful, and so tried to get back on course a bit.
But he also wanted to show what some cash and WETA could do.
Another problem (think that I've stated this many times now, so sorry if I'm playing the tape again...) was that the characters became less interesting as they became more and more caricatures of themselves. Gimli the clown, Legolas the ultimate surfer/warrior, etc. Some characters grew, yet not as much as they did in FOTR.
And I didn't like the ents. And don't get me started (again) regarding Gandalf's staff, which is why I'm here in the first place.
Anyway, note that I'm not saying that the three movies weren't wonderful nor not popular, but just that FOTR will always be my fav.