In various religious circles, Jewish and non-Jewish, you will find some uninformed criticism of the Harry Potter series, arguing that it glamorizes the occult. I should note that the series presents very Jewish values and has been endorsed by such rabbinic leaders as Rabbi Chaim Pollock, Rosh Machal of the Linda Pinsky School for Overseas Students at Michlalah University for Women in Jerusalem (of which my daughter is an alumna and personally heard Rav Pollock speak on this topic).
On a very simple level, Orthodox Jews can find many similarities between J.K. Rowling's wizarding world. Not only do we have a unique culture, although often blending in with the muggle/non-Jewish world, we have our own laws and schools. We even have our own shopping districts -- in Cedarhurst its Central Avenue; in Teaneck its Cedar Lane; in the wizarding world its Diagon Alley. We even have our own unique "uniforms" that identify us to each other, even though those not in our culture may have no idea of what or who we are.
One of the central themes of the Harry Potter books, is, as Prof. Dumbledore says in Chamber of Secrets, "its our choices that define who we are, not our abilities." This is very similar to Judaism's defining verse about free will and righteousness: "...I have set before you life and death, the blessing and the curse; therefore choose life, that you may live, you and your heirs." (Deut. 30:19).
Another similarity is found in Book Six, Harry Potter and the Half-Blood Prince [IF YOU HAVEN'T READ THIS BOOK, YET, BUT INTEND TO, THIS QUOTATION SHOULDN'T BE ENOUGH TO SPOIL THE STORY, BUT YOU MAY NOT WANT TO READ FURTHER], where Dumbledore says about the key prophecy concerning Harry and Voldemort that the prophecy is significant only because you and Voldemort choose to make it so," i.e. if they both chose to ignore the prophecy it would be meaningless. Some will recognize this theme, also, from MacBeth -- had MacBeth not acted upon the prophecy of the witches, nothing bad would have happened, but because he did act on the prophecy, all of the events came true. Interestingly, the Talmud makes a similar observation about dreams at Shabbat 56. There, it is said that two identical dreams could come true in different ways, depending upon how they are interpreted. The Talmud tells us the story of Abbaye and Rava who go to a dream interpreter named Bar Hedya on several occassions. Each time the two rabbis pose identical dreams and seek an interpretation. One consistently gives Bar Hedya a tip, and the other pays him nothing. Not surprisingly, Bar Hedya gives the generous rabbi favorable interpretations, which all come true, and the other interpretations of disaster, which also come true. The Talmud teaches us a lesson similar to Dumbledore -- if one never had the dream interpreted, chances are it would not have come true at all.Now, the insight that prompted me to start this thread.
[BIG SPOILER NOTICE FOR THOSE WHO HAVEN'T READ BOOK SIX.] We learn in the latest volume of Harry Potter that the villainous Lord Voldemort, in his quest for immortality, has learned that he can divide up his soul in pieces and preserve the pieces in objects that he can hide away for safe keeping. In that way, he can never be killed because his soul still lives somewhere. The problem for Voldemort is that in order to divide his soul, he must kill someone, and the process itself -- both the killing and the soul division -- causes huge, undesirable effects (both physical and mental) to the person seeking immorality. Harry, on the other hand, is destined to kill Voldemort for a variety of reasons -- first it is the only way he can live, second, he has to save the world, and third, he seeks revenge. A reader of the current and previous volumes might ask whether Harry's goodness is well served by this mission; won't the act of killing someone, even someone evil, change him for the worst? Guess what? Judaism has explored these issues, too.