Well, "almost" but not quite a plagiarist. I think of this along the lines of, say, Brahms copping the theme from Haydn, or Led Zeppelin cribbing wholesale and obviously from Howlin' Wolf and Willie Dixon (rectified to some extent that they now credit them and pay them royalties). Or, for that matter, Shakespeare and his plots lifted from loads of others. I mean, the parallels are obvious in Rowling. Maybe it's more of a homage than theft -- as T.S. Eliot once quipped, good artists imitate, great artists steal. My point, however, is that Rowling is by no measure a great artist. I'll admit that she has done significant good in getting pre-teens and teens to read again. Bully for that. But the difference between her and Tolkien et. al. is that for all her copying she isn't particularly great, even on a YA lit level, IMHO. Escapist lit is fine in its place. But its place should be marginal, especially if you've matured. My kid, at age 10, got real tired of her for that reason.