I read the books before the movies came out, but due to the amount of obsessing I did over the movie hype, the last time I read LotR I was stunned to realize how my perception of the characters had changed. I vowed not to read it again until I could banish a certain actor from my subconscious. (...and haven't picked it back up again.)
The only characters that came out of my movie obsession unsullied were Faramir and Aragorn, mostly because I found nothing in Viggo or Wenham to admire. 'Cuz you know, the knights in shining armor are only in your imagination...
But I saw the Bakshai cartoons way, way before that - in that at least I take the basic idea for the Hobbits. And Boromir also, come to think of it, horned helm and all.
But most of the formative atmosphere came from the covers of the books themselves - The Hobbit, TTT and RotK were mossy and tan from the Tolkien illustrations, and FotR was the unique Ballantine treefrog in a plum tree with the Riders streaming out of the ford of Bruinen.
Things were a lot more haunting in those days.
All but the first two of my parodies are populated exclusively by Jackson's visions. Sad, as my first two are my favorite.
[edit]
Woah...I just realized how similar Faramir and Boromir are in my imagination...considering how different they were, and how they never interacted on the page, and how I didn't really associate them with each other at the time.