Yes, I did it. I saw the last (?) of Harry Potter this weekend and glad I am, too. [Spoiler alert for those who didn't read the books!]
I'm one of those who believes that every truly human story is a Christian story: that the Incarnation means that Christ came to inhabit all our stories, too, not just to tell stories of his own. Not that Harry Potter is an allegory--it's just a good (and truly human) story that can't get away from its roots in a Christian culture, even though that culture has long since lost its moorings. Even the Latin-derived spells can't help but sound sacramental and (to those who know some ecclesiastical Latin) make "present" to the mind realities that far exceed the thoughts of the fictional characters who use them.
There are two main directions the stories (and that final movie) lead me. One is the theme of power: it is so prevalent a theme that in Harry's world, magic serves the role that electricity serves in ours. There is no electric power in Hogwarts, and the power that is available in that world (just like in ours) can be used for good or ill. Doesn't the use of power reveal the measure of the person who wields it?
In the "Deathly Hallows" Harry comes to posses the three most powerful objects in his world; in the last scene, he is holding the wand that makes him invincible, the "Master of Death." This wand was the object of the evil Voldemort's lust, and (as with the ring of power in Tolkien's myth), even after Voldemort himself was destroyed, the world really wasn't safe while the wand was intact, not even in Harry's hand.
The other theme that pervades the series is that of community. Harry does not ride into town on a white horse (okay, broomstick), a man without a country. Although he was an orphan, he was "adopted" into his ancestral people and brought up, as we learn finally, to give his life for them. But even that he could not do alone. He is supported every step of the way by friends, teachers, even the departed. He is accompanied through most of his ordeals by Hermione and Ron, who also dispatch a Horcrux for him. And that last crucial encounter with Voldemort would have been a stalemate if not for the contribution of Neville Longbottom. Harry is not a savior; he is a member of a community with a unique vocation, who must depend on every other member of the community if he is to fulfill that vocation.
If I were teaching Sunday School, I would find any number of helpful images from the Harry Potter series, things that may be taken for granted by those who get nervous about possible occult imagery and overlooked by those who see the series as pure and simple fantasy.