I was one of the 68 trillion people who got "Half Blood Prince" on the day it came out - though I did at least wait until the afternoon before picking up my pre-ordered copy, and not go to the shops at midnight specially. This may have been partly due to the fact that I had to get up at 4.30 for work (yes, I do work sometimes: yes, in the morning: no, I know that's "not a time" for most people).
It took me several years before I read the first one, and then the pace has quickened through the other five. The initial hesitation was partly due to the furore amongst Christians - I am still conscious of the fact that some Christians would not be happy with their children reading it. This is certainly an opinion they are free to hold, though in defence of the Harry Potter stories, J.K.Rowling's world is apparently a great deal more "Christian" than that of Philip Pullman, in the "His Dark Materials" series,
I had mentally sketched out where I thought the narrative would be going in book 6 and onwards. One of the themes that I had assumed would become more important would be the songs of the Sorting Hat - which has, in a semi-prophetic way, been saying for the last few books that the houses in Hogwarts need to pull together to overcome evil. I assumed that this would lead at some stage to Harry and Snape somehow coming to terms with their past, so that Slytherin could work with the other houses to overcome Voldemort. Suffice it to say that it now looks like this isn't going to happen....
Also, given that Harry's power over Voldemort is the fact that he is able to love, his motivation is drifting rather strongly towards hatred - understandable, but a conundrum that has to be overcome, I suspect. I'm reminded of Luke Skywalker being challenged by the emperor to fight him with hatred in "Return of the Jedi".
Incidentally, for anybody else who ends up here who has read the book, is it only me who thinks that Rowling has left herself an awful lot of loose ends to tie up in what she has said will be the last book of the series?