The cartoon from the 70's was the prequel The Hobbit (and yes, it was pretty good). The Ralph Bakshi version of The Lord Of The Rings came out in the 80's , and it was fuckin' horrible. It condensed The Fellowship Of The Ring and The Two Towers into a lame 2 and a half hour cartoon.
I think Peter Jackson has done an excellent job, so far (and I have no reason to doubt that the next two movies will be just as good). As for Tom Bombadil and the Barrow Downs, the movie is already three hours long (and the special edition is 3.5 hours long). People won't sit in a theater any longer than that, so some parts had to be dropped. I think Jackson picked the right parts. Anyway, I'm really looking forward to The Two Towers. Btw, since it is Halloween, do yourself a favor and watch Jackson's Dead Alive or The Frighteners. Both are great.
-Mark