I only read the books for the first time this year, and I haven't even seen films 2 and 3 yet. I liked the new film a lot, and I was very impressed by the special effects (and the bits when Daniel took his clothes off) but objectively I thought that it was rather unimpressive because of the fact that so many chunks of it were left out. I only understood what was happening, and knew who/what everybody was, because I have read the book. A film should be good enough to stand on its own without assuming that the viewers have read a book beforehand.
For example, the bit at the beginning:
Get up
Walk across a field
Wait for a quidditch match to start
(none of the actual match was shown)
and then a load of death and destruction in the campsite.
All of that bit was cut to the bone so much that it didn't really add anything, and should have been left out completely. It was all over so quickly that it wouldn't have left any useful background information about who or what Voldemort was, or what the fighting was about, to anyone who hasn't read the book.
I have a feeling that in 10 or 20 years time, when the hype has worn off, the film(s) may be regarded as a triumph of special effects over technology.
Having said that, I did enjoy it and I probably will go and see it again.