First of all, please PLEASE pick up the book(s), read them and apply the awesome visuals from the films to what you read. As I write this answer, I have just watched for the thousandth time, the beginning of the Two Towers where Gandalf and the Balrog fall together into the abyss...and hit bottom.....this scene alone is so brilliantly done.....gob-smackery deluxe.
That being said, and being a Tolkien purist with many, MANY years of re-reading the books (ALL of them, not just LOTR, Silmarillion, Lost Tales, History of Middle-earth series....ALL), attending classes, belonging to several of the 1st online heavy Tolkien and LOTR groups and applying the books' teachings to my daily philosophy (geeking out since the '70s)....There is a GREAT DEAL of difference in how Tolkien's rich and tasty tapestry was woven, and how each attempt at making film brilliance out of said tapestry ended up. BUT....
This same silly, bitching argument went round after Ralph Bakshi's WAY abbreviated and reworked animated version came out in the late '70s. I was one of the loudest bitchers....how COULD they replace Glorfindel with Legolas and give him the C3P0 guy's voice?!? And Kemosabe Aragorn...ugh....Galadriel's short hairdo? And that's just the visual wrongness, not to mention the total story changes... WTF!!?? I detested 9and still do) the made for TV Hobbit and Return of the King (gawd.....was that Hanna Barbera??)
Then, a girl said something that opened my eyes like they'd not been opened since my discovery of the books....she said she'd never have given the books a try had she not been captivated by what I thought was rotoscope hell. This awful movie was the cause for a resurgence in the BOOK'S popularity. Making people want MORE. Nothing wrong with that!!
And now, we have the aesthetically rich Peter Jackson version, with no Glorfindel again (yes, yes, I know he's seen at the Council of Elrond). No Stone of Erech. No gazing into Mirrormere. With no ioreth. No Imrahil. No Aragorn discovering the White Tree sapling with Gandalf and then the surprise summoning and bringing of Arwen Undomiel to Minas Tirith. With no Grima Wormtongue slitting Saruman's throat at the threshold of BagEnd after the Cleansing of the Shire. No meeting of the Hobbits and Gildor Inglorion's group and the night under the trees with them near Woodhall. No Fatty Bolger being left alone in the Crickhollow house to pretend to be Frodo too convincingly... ending up running, screaming across the fields in terror as the Black Riders are ordering the door at Crickhollow to "open in the name of Mordor". I could go on for days about what should be there or not because of what is special to me in the books. Pointless...as everyone has different special favourites. I did not miss Tom Bombadil and Goldberry or the Pukel men. Others just whine endlessly about them, as they ask "who is Fatty Bolger?"
What I have ended up seeing instead: another resurgence in the books' popularity. And with these film's creation and all the stuff that's come after, I've made new like-minded friends, other book purists to have deep discussions about the beloved books with....and I don't care how much of a purist you are....these films are breathtaking, beautiful eye-candy (disagree and you can kick rocks). I truly feel the aesthetics surpass what my mind's eye always saw when reading the stories. As a hard-core re-enactor and costume whore, I am forever grateful for the fabu garb design in each of these films (all hail Ngila Dickson).
SO, if you crave MORE, I strongly suggest you take the bait and read the source. There is most definitely more. And THEN some.
And one last suggestion, obtain copies of the extended versions of the films, the extra bits make them so much better....and watch the appendices. You will quickly learn that Peter Jackson and all controlling entities on the films love the BOOKS, have read and re read them for years, know them as well if not WAY better than most fans, and their behind the scenes explanations as to how/why changes were implemented make for less of a sting (did for moi, anyhoo). The video appendices are as enjoyable as the movies for me. I wish they'd not made a story line out of Frodo and Sam having any tenseness between them... Wish they'd not emasculated Aragorn, and wish they'd let him carry Anduril straight out from Imladris as written... but weigh that out with the awesomeness of the visage of Viggo - who will never look better in his lifetime...hmmmm
I have matured to a place where I can take book and film, enjoy the best of both....and ignore that which bothers me. I hope you can read, do the same and hence, find more to love in these epic, magic tales...