I'm torn on whether it should be one or two movies. The book is too long to make one film, but at the same time I don't think there is enough to make the two films.
The wedding and (part of the) honeymoon need to happen for the movie to make any sense. Most of the first bit of the book can be done as added scenes for the DVD release because it's not essential to the over all plot. The 'before' car can just be made reference to in the movie, and if the scene with J and Max is included, just show the 'after' car as Bella, Nessie and Jacob go to get into the Volvo.
Most of the second book fleshes out Jake's character, but at the same time I can't see how it would be important to the final battle. It does answer some questions, like why Jake's pack are at the Cullen's, but I think a lot of that can be cut (don't hate). The one scene I find really important in Jake's book is the part where Bella goes into labour and Edward goes to change her.
If it is two movies I think it should cut out just as Bella goes into labour, but that would make the first half really borning. It would also mean that there would need to be some sort of reminder of what happened at the start of the second one.