Harry Potter and the Goblet of Fire -- When you have to shoot, shoot.
On the plus side, this was the first book in the series so far that made me laugh out loud a few times. Something about Hermione's idealistic but naive obsession with her Society for the Promotion of Elvish Welfare struck me as highly amusing. I suppose it was Ron's insistence on calling the organization "spew" that did it.
This was also the darkest book in the series so far. In it we are finally given a more concrete idea of what constitutes "dark" magic. Dark wizards apparently use the three "unforgivable curses"--the imperius curse, which causes the victim to do the spell-caster's bidding, the cruciatus curse which causes the victim horrible pain, and Avada Kedavra, the killing curse. Now this last one looked so much like the "abracadabra", the all purpose Vaudeville magician word, that I went out and looked it up. It seems that J. K. Rowling herself said that it is an Aramaic spell meaning "let the thing be destroyed." Now why she chose to use Aramaic--the language of our Lord--for this worst of all spells, and not Latin like she did for all the rest is beyond me.
Of course, it should be mentioned that Rowling's distinction between good magic and "dark magic" has never been accepted by the Catholic Church as Fr. Amorth, the famous exorcist, has repeatedly pointed out. That said, to this point in the series, all of the "good magic" has been of the comic-book variety--turning people into ferrets or making someone's nose grow tentacles. The "dark magic" is used exclusively by characters who are unmistakably evil.
One interesting little tid-bit in Goblet of Fire that may be thrown into the Christian-vs.-occult-influence debate happens at the Yule Ball. Up to this point, Christmas and Easter at Hogwarts have been mentioned at least in passing in every book. However, while the British are ever so much less stupid about actually calling the holidays by their proper names (unlike some in the U.S. who insist on calling them "Winter/Spring Break" or attempt to replace them with made-up PC holidays from the 1960s), Christmas and Easter have nonetheless lost almost all religious meaning to most Britons. And thus it has been at Hogwarts--Christmas in the first three books has been all about feasting, decorating, and getting presents. But for a split second in Goblet of Fire, Rowling has suits of armor singing, "O Come All Ye Faithful" (page 395). Given all the secular "holiday" tunes she could have inserted there, that she chose an unmistakably Christian one could be telling. Admittedly, it could also be complete coincidence.
Finally, the aspect of Goblet of Fire that I most appreciated was the introduction of the slimy, ethics-free journalist, Rita Skeeter. This character was such an on-target parody of a gossip reporter that you just know that J. K. Rowling was taking some shots at the media. That Ms. Skeeter worked hand-in-glove with the "Ministry of Magic"--a government agency populated with petty bureaucrats and place-seeking brown-noses--made the parody that much more on-the-nose.
Over all, as a work of fantasy fiction that has been marketed with young readers in mind, I found Goblet of Fire to be quite a foreboding read. The scene at the end where Wormtail mixes a potion in a graveyard for which the vital ingredients are a bone from Voldemort's father, some of Harry's blood, and Wormtail's own hand--which he, himself, promptly slices off--was border-line demonic. And for a book with so much discussion of death, I found it more than a little disconcerting that it lacked any notion of Judeo-Christian eschatology. So again, I will refrain from endorsing this book or the series as a whole as in any way suitable for younger Catholic readers until I see where all this is going.