I've read the LOTR books and the pre-LOTR ring book, The Hobbit (a must read if you want to understand the film/books).
I was really hoping for the missing bits to be in the extra 30min of unseen footage in the fellowship 4 DVD extended set but there was still a lot of the story missing. It'll be intresting to see how much they have to change the movie from the book as the film progresses now..
I'm awaiting my 4 DVD extended set of the two towers and I hope they don't cut too much out (although I can see why they have to).
For these who have the 2 DVD case set, the extra 2 discs are the movie done without the real actors and more like the skech before the production, really intresting to see how they fix up the buildings and what they add in after etc, but of course there is extra things besides that too.
When I first when to see the fellowship I fell a sleep after about an hour into the film. I really had no idea about the people (hobbits etc) in the film. I then read the Hobbit, always thinking it was a chilRAB story I got caught up in it. It was only after reading it did I realise that what the 'ring' was and where it came from. The start of LORT with the voice over didn't go into enough detail (IMO anyway) but that may be due to having read the hobbit book.
If you want to understand the LOTR better and you've not read the hobbit, go get it and read it.
Its just a pitty that we have to wait so long for the 4 DVD set to be released.