Tolkien believed that truth could be conveyed through myth. So, he set out to write a myth of epic proportions, and have his plot guided by truth -- truth in an ultimate spiritual sense. The idea of good vs. evil is obvious, but less obvious are lessons such as: the weakness and hence corruptibility of of the human heart; the idea that "even the smallest of persons can change the world" (as Galadrial told Frodo); the value and strength of true friendship, and true friends; the belief that no matter how difficult a situation or a path, there is a benevolent power that guides all of our paths; the idea that ultimate power can only be wielded for good by the most humble (the point of the book and movie that only a humble hobbit, the least assuming of creatures in Middle Earth, can carry the burden of Ringbearer without being corrupted by the power of it); the parallel truth that only the humble are best suited to possess power; the idea (which is greatly needed in our day) that sacrifice is necessary if evil is to be confronted, but there is a nobility even when evil momentarily overcomes good.
Not to ruin it for those who have only seen the movie, but have never read the books, but in "The Two Towers," there is a resurrection (and did anyone else notice that as Gandalf fell into the depths of Moria, he fell in the image of a cross?).
"Harry Potter" was a good movie, but it lacked any communication of truth. The wizards and witches of Hogwarts wield power, but to what end? For what are Harry and his classmates in training? Do wizards exist in Harry Potter's world for some great purpose? Do the exist to benefit mankind, or as agents of some Higher Power for the betterment of the world? It's never clear. It appears that "Harry Potter" possesses power for power's sake; unlike "Lord of the Rings," where power is used as part of a titanic struggle to defeat an all-consuming evil; and yet the possession of power is dangerous, and is not to be coveted (unlike in "Harry Potter").
I almost hate to contrast "Potter" with "LOTRs" because, in truth, there is no comparison. "Harry Potter" was written as a clever story for commercial purposes. "Lord of the Rings" was written as a means of conveying truth. Therein is the greatness of Tolkien's mythology, and weakness of "Potter."
Ahem. MOST books are written for "commercial" purposes, i.e. to sell copies. If the publisher thought it wouldn't sell, they would never have accepted the manuscript, but allowed it to molder on the "slush pile" instead. And on top of that, WHAT IS WRONG WITH DOING SOMETHING TO MAKE A BUCK ??? I thought support of free-market capitalism was a cornerstone of the Conservative Movement. . .