In some discussions I've had about changes and cuts made to the film of Harry Potter and the Half-Blood Prince, I've found myself thinking where exactly the final two films of Deathly Hallows should be split. It occurred to me that there's a bit of a wild goose chase before things really get started, at least as far as the title goes. Half-Blood Prince leaves off with Harry determined to locate one of the Horcruxes, having realized the one in his possession is a fake. Once Harry, Ron and Hermione begin their quest in the next book, their first priority is finding more Horcruxes. It ends up taking quite some time for them to figure out who RAB is, figure out what must have happened to the Horcrux, and then go about obtaining it. It take longer still before that Horcrux is destroyed. After that, though, before they discover another Horcrux, they find out about the Deathly Hallows from Xenophilius Lovegood. Only after that, and after they are captured and taken to Malfoy Mansion, do they get a clue about where to find another Horcrux. This is, of course, when Bellatrix Lestrange throws a hissy fit over Harry possessing the sword of Griffindor, and Harry deduces that they will have to rob Gringotts. This brings me to about where I expect the cut to be. At the very least, the Deathly Hallows themselves have to be explained in the first film, just so the title will make sense and the non-book-reading audience will know what the point of this part of the story was. The first Horcrux will be destroyed, but we will at least have gotten a hint of where the next one will be, so it won't be left completely unresolved. A major set piece like escaping from Malfoy Manor would make a good climax, and you could break the film there and pick up in the next one with the bank robbery, or you could wrap up the first film with the robbery, and then break it. Whether it will be before Gringotts or afterwards, that set piece strikes me as the perfect mid-point.