I like how some people have been asking whether the fact that the books are simply entertaining should not be enough. Because if LotR was not entertaining then I doubt that so many of us would have read (and re-read) it. Maybe we could have a thread/poll sometime on what makes it such fun to read?
Art does not need to have a deep meaning to be wonderful. If I think of films, one of my favourites is Kill Bill, which has very little meaning (beyond don't cross blondes who are skilled assassins

); it is simply highly entertaining and the only real 'depth' comes from the layering of references and the action/dialogue. I doubt that Tarantino meant for us to find anything profound in it. Another good example might be Monty Python. I would say that the only 'meaning' it has is to get us to think "isn't life absurd?" - it's lack of meaning is it's meaning - yet it is still Art, and it is entertaining.
But then where would we place something which is entertaining but is 'cheap'?
It's too early, my head hurts...