Can fantasy be Christian? If so, where do you draw the boundaries?

I recently taught parts of a series on spiritual warfare in Sunday School.  One of the questions from the class has led me to reconsider some of the comments and positions I adopted in the lesson on the occult. 

There is no doubt but what we are under spiritual attack.  In fact, 1 John 3:8 says "But when people keep on sinning, it shows they belong to the Devil, who has been sinning since the beginning. But the Son of God came to destroy these works of the Devil." (NLT).  I use the NLT translation here because it clearly conveys the continual aspect of sinning, not just a once in a while event.  To curse once a quarter may be nothing more than your sin nature trying to get a grip on you.  To curse as a part of natural speech falls under the concept of this verse.  John says that all continual, habitual sinning is caused by spiritual warfare.

If this warfare is all around us, we should carefully consider how we live and react to events of life.  We are called to be Christlike and Paul tells us we have the mind of Christ to accomplish this task (1 Cor 2:16).  We have the weapons if we will only use them.

Anyway, the class discussion focused for a period on fantasy fiction, both written and in the movies.  Was it part of Satan's attack?  Where do you draw the battle lines?  In particular, is there a difference between Harry Potter, The Lord of the Rings, and The Narnia Chronicles (i.e., The Lion, The Witch, and The Wardrobe) of C.S. Lewis.  Where does the difference reside? 

This may, or may not, present a more complex issue than appears on the surface.  For example, almost "everyone" who writes on the topic views Narnia and the Middle Earth stories as Christian, but there is a wide disagreement when it comes to the Harry Potter stories.  Is there?  Should there be?  How should we view fantasy as a category? 

These are questions I am pondering.  Perhaps, they have the making of future polls.  In any event, I will eventually post my thoughts either here or as a new study on the site.  In the meanwhile, I welcome your thoughts and comments.

Jim