Hugh,
I am in partial disagreement with you.
I saw the first screening of the movie just after midnight when it opened (not due to fanatacism; I just happened to be with my brother when he suggested that we go see a midnight movie, and that was one we could both agree on). Both my brother and I really liked the books, but we were both rather disappointed with this movie. (By the way, we got right in with no lines. I think this lines & crowds thing is because of the area where you live, Hugh.)
Yes, it was visually stunning. However, it left out more parts of the book than it included, and was ultimately somewhat incoherent. For people who are familiar with the book, it can certainly be enjoyable as sort of "a visualisation of select scenes from the book"; but... in my opinion... the movie must be complete in of itself, and this movie did not stand on its own as more than a visual companion of select scenes from the book. So, I might recommend this movie to folks who know the book, but I wouldn't give it an unqualified recommendation to someone who is not already familar with it.
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WARNING: ** SPOILERS **
Regarding thoughts about Harry Potter and the Half Blood Prince, and the next book:
Firstly, Snape is obviously on the side of good, against Voldemort. I expect that we will find in the next book (I'll tentatively call it Harry Potter and the Hamper of Dirty Linens

) that the reason Dumbledore could always unfailingly trust Snape is because of some Unbreakable Vow that Snape had chosen to make with Dumbledore.
Snape's fundamental goodness and his siding against Voldemort also explains why, when he dueled with Harry during his escape, he took the occasion to give Harry a lesson about how he will need to learn silent spell-casting and Occulmency in order to win his fight against Voldemort.
I also expect the next book (HDL for short

) will make clear that, when Dumbledore was pleading with Snape, he was not pleading for his life. Do you recall, in Harry Potter and the Sorcerer's Stone (Philospher's Stone, in the original British versions) the scene at the end of the book where Dumbledore tells Harry that he spoke with Nicholas Flamel and they decided to destroy the Sorcerer's Stone? In that scene, Harry asks, (paraphrasing) "doesn't that mean Nicholas Flamel will die?" Dumbledore answers yes, and then assures Harry that for Nicholas and his wife, it will be like going to bed after a very long day. Dumbledore goes on to explain to Harry that he sees death as just the beginning of the next great adventure. So... would it make sense for someone who takes that perspective on death to plead for his life? I think not.
Then what was Dumbledore pleading for? My best guess, is that Dumbledore was pleading for Snape not to blow his cover in Voldemort's innermost circle of Death Eaters.
Which brings up the question of whether Dumbledore did, in fact, truly die. I can see this going either way, and won't make a prediction about this, but there is certainly a plenty strong case to be made for how he could be alive. As we learned throughout the book, Snape has mastered casting spells silently, so it is feasible that he could've cast an entirely different spell while merely saying "Avada Kedavra". This would explain why, when Snape pointed his wand at Dumbledore and said "Avada Kedavra", the spell that was described was entirely different than the way that the death curse is described in all other instances throughout the series. (Throughout the series, it just causes someone to instantly slump over, dead; in this one case, it forcefully blasts someone back off his feet.) How could Dumbledore have appeared dead, if he was not? Remember that potion which makes someone sleep so deeply as to appear dead? That's how.
Whether Dumbledore is dead or not, I'll make two related predictions: 1) He is not simply out of the series; he still plays some part in the final book. If he's dead, then (A) Harry should still be able to consult with Dumbledore's portrait in the Headmaster's office; (B) Dumbledore said quite clearly (In Harry Potter and the Chamber of Secrets, in Hagrid's cabin, when Harry was hiding under his cloak, when Lucius Malfoy told Dumbledore that the board of Governors was removing him from the position of Headmaster) that, even if Dumbledore bodily left Hogwarts, that part of him would be there, as long as anyone loyal to him still remained at Hogwarts, and that those in need would still receive help. My other prediction (2) is that even if Dumbledore is still alive, we've come to the point in the arc of the series where Harry has matured enough that he must stop behaving stupidly, must become pro-active, and must, to a large degree, go it alone.
A few final, more way-out-there predictions, for fun:
Petunia Dursley is a witch or a squib.
Voldemort made into a Horcrux something or someone very dear to Harry, which Harry won't want to have to destroy.
We will see that the conversation between Dumbledore and Malfoy, shortly before Snape zaps Dumbledore, is the moment where Malfoy chose the side of the good, against Voldemort.
Harry's power which the Dark Lord knows not... love, as Dumbledore explained to Harry... is going to somehow involve forgiveness and/or redemption with Malfoy and Snape.
Whoever "RAB" turns out to be, will be helpful to Harry in preparing for the final conflict with Voldemort. The only guess I can come up with for the initials "RAB" is Regulus Black (whom I know is supposed to be dead).
Ron and Hermione will "Snog".
And really out on a limb:
Perhaps McGonagall is an undercover death eater? That would explain what would otherwise seem like a minor error at the beginning of the first book. Probably just an error...
Mike