I was pleasantly surprised and enjoyed the movie. I have read all the books, and in having said that, I do think it was helpful to have read the book before seeing the movie. It is hard to fit almost 600 pages into a two hour movie, and I was able to fill in blanks or add to what I saw by having read Twilight.
I was happy with the casting and I think the film makers were conscious of the fan base and tried their best to please. I am eagerly awaiting the next installment.
I have a friend who hasn't read the books but heard about them from me, she went to see the movie and loved it. We both plan to buy the movie when it comes out on DVD. The soundtrack is really great too.