The Hobbit (1977): *laugh* You know, there's something very John Denver about these cartoons. :-) That's not a bad thing; I really like the music, actually. It sure shows its age, though.
This one followed the story more closely than The Return of the King (1980). In fact, Beorn's absence is the only disparity that comes to mind. Unfortunate, seeing as I always liked him.
I really liked the animal animation. There was something very Princess Mononoke about the Lord of the Eagles. Smaug too. He was one of my favourite parts. They missed such an opportunity with his belly - it could've been so bejeweled - but his voice and movements were great. Very feline.