Harry Potter. Extremely controversial among Christians.
Which is exactly why I chose to read the series.
(and of course, having friends who are big fans helps =P)
From the beginning, I was pleased. My first concern was with the fact that the entire series was about a school of wizards. That was taken care of within a few paragraphs.
I have been a fan of the fantasy genre since reading the Lord of the Rings. Both the stories of Middle Earth and the Chronicles of Narnia contain what one might rightly call "magic". On further observation, Gandalf's powers are shown to be a natural ability, not one gained by delving into dark things. And the White Witch is just evil, aside from that.
The same can be said of the wizards in Harry Potter. They're nearly a different race, like Elves. Wizards are born with natural magical abilities.
"But they're going to a school to learn how to develop those abilities. How is that different?"
Honestly, I'm still not quite sure how to answer that. Really that's just how I see it, and it's one of those things you have to decide for yourself. If there's a better explanation it's one of those thoughts I can't word.
And yes, there are "Dark Arts", which is a side of magic that most wizards frown upon. Some things mentioned are forbidden curses --such as torturing your enemies, or using the Killing Curse-- or splitting your soul as Voldemort did (really, I think those kind of things are unreasonable. Don't you? =P). There is actually a class at Hogwarts teaching students how to defend themselves against the Dark Arts.
There are no instructions on how to do such things, or anything that could pose a danger. It's the evil side of the wizarding world --and what's a story without bad guys?
I'm not saying that everyone should read the series. In fact, one should be discerning about picking up any book, and this is not an exception.
The magic itself struck me as a fairy-tale sort of thing. Spells are derived from Latin words, and things such as seeing the future are actually laughed at. The "Killing Curse" sounds a lot like abracadabra. You can't take any of it seriously, and therefore I do not think it poses a danger in and of itself.
I do see where there may be a problem. The first two or three books, at least, are almost children's books. Harry is just turning 11 when we first meet him. Those who started reading the series around the time the books were first released pretty much grew up with the characters.
While the series is safe for someone my age, I'm not so sure about younger, less discerning readers. The books also take a darker turn around the 5th book, as the characters grow up. I find no harm in fiction, as long as one keeps in mind that it is only fiction.
Aside from the magical aspect, I really enjoyed the series. Rowling's writing is amazing, the stories are really clean (mainly a few swear words --minor, though possibly another problem for kids-- and characters falling in love --again, pretty clean), and somehow you can't help but love the characters.
It's one of those things that is up to you to decide, but personally I'm glad I decided to give this series a try. I think it'll enjoy a nice long life.