Bloody brilliant!  The confrontation between Snape and Harry was classic, and we see that we are getting a manipulative, I know best so do what I say and put up with what ever crud I heap on you Dumbledore in this chapter as well.  I think you've potentially set the stage for some of Harry's friends to have a "discussion" with Dumbledore and Snape.  Ben Grimm could be interesting "It's clobberin' time!"  Of course, there are numerous others that could be entertaining as well.