Not a fan of the Potter books myself. That said, they have been absolutely incredible in getting young people into reading, more so than any other book series. Rowling is a superb writer.
Neil Gaiman. Anything by Neil Gaiman. Neverwhere and American Gods alone both make potter look like dick and jane with food poisoning.
Here, Here, there is quite a bit better in the genre that surpasses and supercedes the tripe of Harry "O'donnel(as it turns out*)" Potter *if you've done your research