I too love the Cate Blanchett voiceover at the beginning - her voice has a wonderfully mysterious quality, and I agree with
radagastly - first time viewers don't know who is speaking, so there's not yet a connection with Galadriel. Besides, the beginning is the mythological background, and Tolkien's Legendarium was written from the Elves' point of view. For that reason alone no other race could have taken over that part.
For the same reason, (the beginning being mythological) I actually like the stylized images at the beginning. Unlike
Underhill, I don't expect a realistic approach to this part of the story. It's like a painting of an historical event - we know very well that it didn't look exactly like that on the actual scene, but the artistic point of view shows symbolic details that give those who view it later information and "truth" despite the lack of realism. I guess I would apply that to the Elven sword-fighting - who cares about realism when it looks so cool?!
I think the color theme chosen for the two forces is very good - gold as a symbol of light for the Elves and allies, black/grey for the orcs and cohorts, to show darkness. Interesting detail - we see Elendil's helmet only very briefly, but it is the one Aragorn wears at his crowning later. The one thing that grated with me in the battle was the fact that Elrond wears no helmet. I know his face has to be shown so that people recall it when he appears later, but having him bare-headed in the middle of helmeted soldiers seems silly.
I too like the sound effect of the falling ring in the cave - it sounds very heavy, not at all what one would expect of so little an object. That of course shows how "weighty" it is in the context of the story.
We have one visual element that is used occasionally in all three films - the map. It gives a brief sense of orientation and makes the fantasy world feel more real. Having it underlying the pictures of Sauron's destruction of Middle-earth (those look like they come from the Rohan scenes in TTT) gives that scene a sense of broadness in scope. Also, a map is used for the transition to the next scene, Bag End in the Shire. Whoever did the map drawing did an excellent job of recapturing the Tolkienish look; they were very close to the original book maps.