Any word on where they are going to break off at the end of this movie? The rescue from the Malfoys' place would be a goodplace to stop. Then storming the Bank and the Battle of Hogworts would take up the next movie.
I remember reading somewhere (I beleive it was on Wikipedia for the entry on HP & the Deathly Hollow movie) that the 1st part of the movie would end at the conclusion of Chapter 24 (I do not have the book on hand so I cannot provide you with any more detail). I also remember reading (I beleive in an interview with Emma Watson) that the 2nd part would mostly contain the Battle of Hogwarts.
It will be interesting to see the differences between the book and the movie. From the trailer, it looks like the scene where Harry finally leaves the protection of the Dursely's house, takes place throughout the city. In the book, the characters just manuever through the air over the English countryside.