This 12 disc set is amazing. 2 discs each for the 3 movies, and 2 discs each for preproduction/production/post production information.
I used to think buying movies with special features (i.e., movie in the making peeks) was just a waste of money, but being a LOR fan I just had to have the extended edition set, and, Lo and Behold! ..I had as much fun watching the special features and it made me appreciate the movie more. My husband wasn't much into LOR (he isn't a 'reader'), but now he's a fan as well. We found everything else on TV boring after watching it when we got it for Christmas.
Plus, you can watch the movie 4 times more with different audio commentaries from cast and crew. It was worth it!