I loved the movie!!! It's my favorite so far. This happens every time one of the movies come out - some people will love it for how much it did represent the book, and others will complain because it didn't get everything in or changed some parts. I don't agree with EVERY decision the filmmakers made, but in general, I think they got it right. Like with the last two, it's a long book, and they couldn't have included every last detail without making the movie too long or too rushed.
I do wish they had left the battle of Hogwarts at the end instead of burning down the Weasleys' house. The rationale I heard was that they wanted to create the feeling of danger in the middle of the movie... They felt it was too light and funny and wanted to remind you of what was going on in the rest of the wizarding world. That makes sense I guess, but I still would have rather had the even bigger finale, at Hogwarts.
I know Bill and Fleur will be in the next one, so they'll just have to catch up on back story with them then. They already had Tonks and Lupin together in this one as well. But really, neither of those couplings were that important to the overall storyline of this book, so I can see why they cut them to simplify a bit.
As for the house-elves, I'm sure they'll be in the next movie, but at the same time, the impact of what happens with Kreacher and Dobby in Deathly Hallows won't be as great in the movie as it was in the book because they did leave out so many times where Dobby helps Harry over the last three books, etc. I wonder if they did that because Dobby was kind of annoying in Chamber of Secrets LOL. They didn't want him to become the Jar Jar Binks of Harry Potter.
I wondered about the Horcruxes too... They'll have to figure out how to get around that, but it would have been smarter to have just added five or ten minutes to the movie of Dumbledore showing him snippets of those memories and telling Harry his theories.
At first I thought the same thing about Harry in the scene on the tower... but thinking about it more, I'm okay with how they did that. Dumbledore told Harry to trust him and to obey him, and Harry did. That shows his trust in Dumbledore. When Snape came up, WE all knew what was going to happen, but Harry would have thought Snape was coming up to help fight off the Death-Eaters. He wouldn't have said anything because he would have blown Snape's cover that way. The fact that he stood there and watched it all happen will make him feel more guilty about not doing anything than he did in the book, where he physically COULDN'T have done anything. And it will probably shake his trust in Dumbledore more too, because he trusted him and obeyed him when he, in his mind, shouldn't have.
The books will always be way better, but I do like the movies.