Odo Proudfoot said:
Other, more famous scenes from the book like
Weathertop,
Gandalf against the
balrog on the Bridge, the
Argonath, the arrival of the
Rohirrim on the Pelennor,
Eowyn slaying the
Witch King, the final moments at the Crack of Doom,
the Grey Havens, are conveyed in the films
equally well as in the
books - their impact in both book and film is equally enormous.
And of course there are a lot of moments which are still better in the book than in the films, or do not appear in the films at all. No argument there.
Odo
My opinion on these:
Weathertop: the book made
much more sense.
Frodo is not a wimp in the book, he defies the wraiths. He shouts the name of
Elbereth (and according to
Aragorn this was more painful to the Witch-King than Frodo's stab at his clothes). And of course we get an explanation on the reason for just 5 wraiths.
Gandalf x Balrog: the movie is better. It was beautifully done, both in FotR and in TTT. I think even JRRT would be moved by those scenes (except perhaps if the Balrog did
not have wings

)
Argonath: again, a plus for the movies. The book is incredibly moving, but that's the magic of movies... to see those
statues was amazing.
Rohirrim at Pelennor: no way

. The book is
much better. We don't have the darkness in the movie! The lack of
Sauron's darkness spoiled the Battle of Pelennor for me. Associated with the lack of Sauron's darkness is the lack of any sense of ominousness; there was no moment in which I feared that the good guys would lose -- and don't tell me this was because I had read the book! No, in
Helm's Deep (TTT) the feeling of despair was much better conveyed. 300 vs 10,000, Aragorn and
Legolas arguing about it, only old guys and children... it was much more moving than the Siege of
Minas Tirith. And this is a big minus for the movies.
As for the charge of the Rohirrim, where is the c*ck (male of hen) that sang, greeting the unexpected dawn that was too early for Sauron's plans?
Éowyn vs. Witch-King: books are better, again -- and very noticeably. I think the
Fell Beasts are too huge in the movie, for one thing (Éowyn beheaded one with a single blow in the books). But the Witch-King is simply... not scary. The whole scene is badly timed (compared with the book).
Crack of Doom: a tie here. That means I agree with you Odo

.
Grey Havens: it's nice in the movies, but in the books it is better. This is because the ending of the movie is too rushed. We don't get the sense of the ending of the Fellowship. The other guys (
Gimli, Legolas) simply disappear. Hopes for the EE...
You earlier talked about the
beacons, and F&S in the rock after
the Ring was thrown. Frankly, the beacons were... ridiculous, for me. They ruined my "suspension of disbelief". There are magical things, and non-magical things. The non-magical things are, well, non-magical. It is impossible to assume beacons placed like that, on the top of outrageously high
mountains. As well as being a useless maneuver by Gandalf at that moment -- assured to annoy
Denethor only. The rock is poignant, but so is the portion of the book dealing with it (the "old Frodo" resurfacing, and being glad to be with
Sam, "here at the end of it all"). I'll give it a tie.
These are my thoughts on comparing book and movie. Looking at the movies on their own, my favorite is still FotR. But I'll wait for the EE of RotK to give my final verdict.