*Small Brain enters rather intelectual discussion*
I'm going to put my two cents in here, seeing as this is a pretty good subject.
First of all I just want to say a few things about the Harry Potter books. I'm sure that the books may be well written as far as books go, seeing as they're so popular. I haven't read them myself, or seen the movies, though. Growing up in a Christian Home in the middle of Nowhere, I have been taught a great many things about using discretion in reading different kinds of books. (I have a habbit of having a little bit of a too-active imagination, of which has made my father think I'm going to end up in a nice padded room. Go figure.
) I am tempted to read the Harry Potter books to find out why the controversy, but here are many of the reasons that many of my fellow Believers do not approve of the book.
1) Witchcraft
2) The undefined line of good and evil
3) The fact that many of the "good guys" lie to get what they want
Don't be offended by my writing, please. I'm only writing what many people have told me, who have indeed read the books.
Now about LOTR. I don't believe that it would ever cause any controversy, because even though it has Wizards in it, Magic is not the only factor in the Story. We have the power of love, the human spirit, friendship and friends who are willing to die for what is right. The Bible says: "Greater love has no one than this, that he lay down his life for his friends." (John 15:13) We see this so many times in LOTR, Gandalf in Moria, Boromir at Amon Hen (Amon Hen, right?), Eowyn almost died protecting Theoden. There are so many cases which reflect Professor Tolkien's Christianity.
Also, no matter what era you live in, there will always be opposition for any book, wether good or bad. I have several cousins who refuse to read Lord of the Rings because...... Weel I don't know. They're very legalistic and judgemental, and believe that any material you read other than the Bible must be dull and unimaginative. Anywoot, I agree with everyone who said that it was better accepted because of the Christian backdrop of the story. Even though Professor Tolkien did not write it as an alagory, his Christianity shows through in his works, shining with love for the story and for the reader.