I spoke with Matthew Lewis briefly at Dragon*Con in Atlanta this past weekend, and asked him a few questions about the screenplay for HBP. He said he was very pleased with this one, he feels like it stayed extremely close to the book. Some things were cut, of course, and they added one scene in (with Rowling's approval) that added to the pacing and gave it a more tense, desperate feel.

I told him that I was looking extremely forward to Daniel & Bonnie's H/G scenes together and his eyes brightened and he grinned: "Oh yeah, that stuff is brilliant! With Harry and Ginny and Dean, it's all really, really fun, and it's going to be great to watch!" He sounded very enthusiastic about it.