In Sorcerer's Stone, most of the little things I caught were just that. Little things in the context of the book itself that I'd forgotten she'd made reference to until they became important in later books. Dumbledore making reference to the letter that he left with Aunt Petunia, Hagrid giving Sirus back his bike, Fred and George being "twins" ( I can't wait for her to explain what that means. My working theory is that it's ultimately going to have something to do with why they are in the same year at Hogwarts and why they look so much alike.) It was little details like that there was really no reason to notice the first time around that really tickled my fancy this time.
In Chamber of Secrets the forshadowing gets a lot more sinister and while I loved the book and while the CoS movie was the film that really sold me on a Harry Potter film franchise, knowing what I know now, the book has a much darker bent. In my last Potter-post I discussed how Voldemort is always a threat to Harry and that he was never watered down as a bad guy. However, after reading 1/2 Blood Prince you realize just how much danger she was really putting Harry in very early on.
Riddle's diary, the first time I read the book, was, I thought, a really original and ingenious device. Now, however, knowing what the Riddle diary is, it gives CoS a very different feel. It also she'd more light on Dumbledore's belief that it is Harry's capacity to love that is his greatest weapon in his feud with the Dark Lord. In the Chamber of Secrets Harry is handling, dealing with and ultimately destroying one of the foulest inventions that the dark arts has ever cooked up. Harry doesn't wind up in the fetal position on the floor because, A.) he doesn't know what the diary is and B.) His best friend's sister is in mortal peril. He is so concerned about Ginny that he doesn't have the time or the inkling to worry about much else. This is a mindset that Voldemort has never known and will never know. In fact, given what we now know about Voldemort's psyche, it's very likely that the part of Voldemort that inhabits the diary believes that Harry is fighting his pet and his book out of a sense of destiny. He's not even using Ginny as bait per se. He baits Harry and Dumbledore in the message that he makes Ginny scrawl re: the final resting place of her bones but he's dragged her down there to eat her essence and strengthen himself.
Two other thoughts before I sign off, the first being that Gilderoy Lockheart is one of the few characters that the films have changed my visualization of in the books. There's just something about Kenneth Branaugh's portrayal of Lockheart that just rang disturbingly true. Maybe it's because he doesn't really have to act to play a convincing pompous ass with an undeserved since of self-satisfaction.
The last being yet another musing on whether Voldemort being Slytherin's heir actually means jack-diddly-hoo-ha-crap anywhere outside of his own mind and the minds of his followers. There is an implication in this book that Sallie himself might not have approved of Voldemort's method or his mantra. He was Godric Gryffindor's best friend don't forget. When Hermione brings up the Chamber in History of Magic, the ghost-professor's explaination includes the fact that tensions between Muggles and Wizards were particularly high when Hogwarts was founded. It is also specifically mentioned that Slytherin didn't want to teach muggle-borns specifically because he didn't trust them. Therefore, Slytherin himself might have been less of a biggot and more of a paranoiac. It's a pretty well established fact that Muggle born witches and wizards can be badasses. Hermione, Lily Evans/Potter, etc. If a war were to break out between the Muggle world and the Wizarding world, someone like Hermione's loyalties would be sorely tested. Does she side with the world she belongs in or with her muggle parents who have loved and cared for her all her life. Slytherin might have wanted to only teach fullbloods out of a fear of possibly arming foes of the wizarding world so to speak. That would also justify putting a creature as dangerous as a basilisk in the Chamber. Excessive, yes. Dangerous, yes. ended up doing a lot more harm than good, absolutely. However, it still might have been a plan crafted out of fear of witches and wizards siding with the muggles should things get bad.
The dogma itself though, when stripped of its context provides an excellent canon of bigotry and classism which Voldemort and his cronies have bought into completely. I for one, kind of like the notion that were the Dark Lord's deified ancestor to turn up in the modern age there would be an excellent chance that he'd be shocked and apalled by what his decendent was doing in his name.