In an interview with the LA Times, Harry Potter and the Deathly Hallows director Terry Yates discussed, amongst other topics, the splitting point between the two currently in production Harry Potter and the Deathly Hallows films.
At this time, Yates confirms that he has selected where the split will occur but it could change depending on what happens during the editing process. In other words, nothing is set into stone until the first film has been pieced together and signed off on.
Yates describes the preferred splitting point as occurring shortly after the scene where Harry, Hermione and Ron are captured by the Snatchers after being chased through the woods. Ironically, that is the very scene Yates was shooting when he took a break to give the LA Times a jingle on the phone.
He goes on to describe the split as a cliffhanger, something the Potter series has yet to see but makes sense given both Deathly Hallows films come from one single book.
So Potter fans, put those thinking caps on. The split is a cliffhanger that takes place shortly after the forest sequence. Do you know what it is? Chime in with your guesses in the Comments section below.