Will I see the movie? I don't know, am I willing to watch one of my favourite characters die? [/sarcasm] (I did that in movie 5...)
Well, as for my opinions on the last five movies:
Sorcerer's Stone: Did a very good job of following the book. When I first saw this movie, it cleared up a LOT of stuff I was confused about in the book.
Chamber of Secrets: Also did a good job of following the book. My favourite character in this one was Lockhart, especially with the little bit after the credits. That really cracked me up.
Prisoner of Azkaban: I was disappointed with the new Dumbledore, but other than that, I really liked it. I was surprised at how well the time-turner scheme played out, and didn't see any characters butchered (not even Lupin and Sirius).
Goblet of Fire: My least favourite of the movies so far. I didn't particularly like the book to begin with, save the parts at the Quidditch Cup and the tasks perhaps. This movie did a poor job of following the book; it left many parts out, like Harry's conversations with Sirius (save one lousy one in the fire) and over half of what happened at the Quidditch cup. When I saw it recently the primary thing I kept thinking about was Edward from Twilight, whenever Cedric appeared.
Order of the Phoenix: This was my favourite of the books, and also my favourite of the movies so far, even though my favourite character died in it. Because the book was long, I was afraid of the movie not following it well, but actually it did a very good job. It even omitted a boring part near the beginning of the book.
I'm very excited to see how the sixth movie will play out, especially the adventures Harry and Dumbledore embark on together near the end.