Tolkien being a writing genius had the most to do with it. Every single aspect of the movies and books were complete, there wasn't shitty directing, acting or anything thing like that. Just a bunch of dedicated, talented people coming together to make a masterpiece.
It had a healthy balance of fantasy, drama, grit, subtle humour and wasn't infested with references to other existing works of fantasy or current popular culture. I was impressed with both the books and the movies, personally.