Samnell
Explorer
I guess Chihiro was a little annoying in the beginning of the film (no more so than most preteen girls I've ever encountered), although given her oafish parents, I think you can see why. I think the point of the film is that she starts this adventure as a whiny kid, but over the course of events she finds reserves of strength within herself that she didn't know existed. Compare her at the film's opening to the film's closing, and I think you'll see what Miyazaki was trying to do. It was a tad heavy-handed, but it rang true.
I know what he was trying to do. But squealy anime girls (regardless of how realistic they are) are one of the things I find most aggrivating. It's right up there with trailers that spoil every worthwhile scene in the film.