I have read and re-read Tolkien's books for many years...even the Silmarillion. I have cherished reading and discussing these books with my sons as well. I'm sure like many here I had visualized the scenes, characters, and events in my mind. I doubt that any of us would have the exact same concepts and so Peter Jackson's vision is different than ours.
I must say, I really loved the LOTR movies. Yes, there were a few things that were changed, added, or omitted, but all in all, I can't imagine a better translation of the books into movies. In fact, in almost every case, the characters and scenery were so much better and more detailed than I had imagined in my own mind. Like Moria, for example! The complexity and attention to detail astounded me.
I equally enjoyed the first two installments of "The Hobbit" and I'm eagerly awaiting the third. Did Mr. Jackson take more artistic license with these two movies than he did with the three LOTR movies? Yes, he did. Even so, I very much enjoyed the movies. They are an interpretation of the story, and not a word-for-word usage of the book as the script. I've rarely seen a movie made from a book that was totally (or even close) faithful to the book. In some cases, like "The Hobbit", it works for me since I didn't find the main characters and main events changed, and again, the visuals were so well done in my opinion. (I could quibble a bit about Beorn's appearance in human form...I had pictured him as more like Paul Bunyan and in the movie he looks more like Wolverine.) I've seen some movies based on books that you couldn't even recognize the relationship between the two.
A note about the quivers that never run short of arrows: it's a Hollywood touch equal to the good guy's gun. For example, in "Open Range" there is one gunfight scene where Kevin Costner's character shoots 14 times without reloading from one of his 6 shot revolvers...quite the achievement! (When asked about it, Costner admitted that he knew it was incorrect, but didn't want to interrupt the flow of the scene with a reload...or two.) Sometimes we just have to suspend disbelief in the interest of the bigger issue: the story.