In a New York Times piece, linked and commented on in Metafilter, author A. S. Byatt mourns the state of current fantasy literature, particularly Rowling’s Harry Potter books. Byatt refers to such books as “secondary secondary fantasy.” According to Byatt:
Ms. Rowling’s magic world has no place for the numinous. It is written for people whose imaginative lives are confined to TV cartoons, and the exaggerated (more exciting, not threatening) mirror-worlds of soaps, reality TV and celebrity gossip. Its values, and everything in it, are, as Gatsby said of his own world when the light had gone out of his dream, “only personal.” Nobody is trying to save or destroy anything beyond Harry Potter and his friends and family…. Ms. Rowling, I think, speaks to an adult generation that hasn’t known, and doesn’t care about, mystery. They are inhabitants of urban jungles, not of the real wild. They don’t have the skills to tell ersatz magic from the real thing, for as children they daily invested the ersatz with what imagination they had.
Essentially, what Byatt is saying, is that she doesn’t like Rowling’s books because they aren’t the sort of fantasy Byatt favors; she then uses her personal taste to bludgeon Rowling’s Harry Potter books, and the taste of those readers who do like them, condemning them as "secondary secondary" fantasy.
She’s missing something rather important. I too very much like Susan Cooper, Diana Wynne Jones (warning, Flash site), Tolkien—and a host of others like them, for instance, Patricia McKillip’s RiddleMaster of Hed, or Lloyd Alexander’s Prydain Chronicles . . . or, oh heck here’s a page I made. The books Byatt favors, and that I very much like, are derived from or influenced very strongly by medieval Celtic myth, and, in Tolkien’s case, Germanic and Finnish traditions.
Harry Potter is descended from an alternate tradition, that of Victorian children’s fantasy. The tradition includes the books of George MacDonald, E. Nesbit, and the "allegorical" member of the Inklings, C. S. Lewis. Victorian fantasy has as legitimate a pedigree as the Celtic stuff (which also has a Victorian heritage in the the Lady Charlotte Guest translation of the Mabinogion).