I'll toss in my thoughts as well. My gf and I went to the midnight showing Friday, and it solemnly affirmed my belief that there should be a curfew where I live for small, annoying children

That aside:
Acting:
Gambon needs to read the books and realize what he needs to be doing. We don't see Dumbledore really angry until the Dept. of Mysteries scene in OotP.
Moody could have been done better. He didn't seem to be grizzled enough. Maybe I'm wrong, but my impression of Moody is that he's rather like an overdone steak.
Ralph Fiennes (Voldemort) - A+. Perfect.
Everyone else was about what I expected, although I must admit I did enjoy Alan Rickman's being passively humorous.
Story:
I do undertand that it's very hard to accurately get a 700+ page novel down to a 2 1/2 hour film, but some things were just too much. The abscence of a Quidditch match left me disappointed. I understand showing Quidditch is supposed to be all about Harry, but they could at least have done something. The first task scene was nothing more than a car chase albeit one writ magically large. I'm also wondering why they cut Ludo Bagman from the film. I can understand why they did it with Dobby, as he's somewhat annoying. Additionally it gave Neville the chance to be somewhat more prominent (I think there's going to bemore to him than is let on). The mosh pit at the ball could have been done away with as well. Also, the maze was supposed to have been built on the Quidditch pitch, not something that seems like miles and miles of hedge. I also noticed that when Krum was cursed in the maze, his eyes were glossed over. The Imperius Curse doesn't leave physical evidence, and that's something important to both how it works and to the backstory in general.
Other stuff:
The cinematography was fairly good, if a bit dark. While I understand that GoF is in a way the low point of the series with Voldemort coming back, the whole film didn't need to be so dark.
All that being said, my aforementioned girlfriend wants to see it again, and I'll probably oblige her. A- overall.