These are not meant to be one to one correlations, just a reminder on that.
It struck me that Harry Potter is not the only Rowling character who corresponds to Frodo. Who is it that is given the almost impossible task? Who faces death? Who is it who must struggle through until the bitter end? And who is it that is saved from doing the most horrible thing that could be done, by the supposed betrayal of another? Yes, Frodo in LotR; but who in HP? Draco Malfoy. And Snape saves him from murdering Dumbledore by doing so himself.
Murdering Dumbledore I find to be akin to
claiming the Ring. It would have been the point of no return for Malfoy, and he is saved from it. He isn't even completely willing to do it, as Dumbledore assures him that he is no killer; but would become one if he had followed through. So Snape is akin to Gollum, and Malfoy to Frodo. See it?
By contrast, what's HP's primary title (whether he likes it or not) through HBP? "The Chosen One". Who's the chosen one in LotR? Isn't that more of an Aragorn type role? It's interesting, however, that Malfoy's struggle is seen at third hand instead of at first hand. (um, so what would be second hand? heck I don't know
)