I went to watch Harry Potter and the Order of the Phoenix yesterday.  In order to get the best seats, I had to book the ticket 3 weeks in advance.

Watching this movie was one of the two activities I longed for after the New York trip.  To my great disappointment, neither the movie nor the 3D effect was satisfactory.

I admitted that the big screen of iMax in MegaBox did give me a thrilling experience when watching the movie and some of the 3D effects were fascinating.  However, during the 20-minute 3D show, apart from the flying thestrals, I didn't find any other scenes that would give me 'oophs' and 'aahs'.  The scenes of the crashing orbs in the room where the prophecy lies and the shattering glasses in the Atrium of the Ministry of Magic where Dumbledore and Voldemort fight could have been more dramatic if the special effects team had made the orbs and glasses fly towards the audience.

Personally, I think the 3D element in this film is just a gimmick to make up for the plot. 

If you have read the original novel, you will agree that the plot of Book V is a bit complicated.  There are quite a lot of characters, trivials and events in Book V.  It's not like the other four books which focused on ONE big mission each time.  Therefore, it makes it difficult for scriptwriters to squeeze everything into a 2-hour movie.  They have to edit the original to suit the making of the movie.  Finally, for those who have read Book V may find the movie version missing too many details.  But for those who haven't read the Book may not have a clue for what's going on in the Ministry and with the prophecy.  

I have decided not to watch Harry Potter and the Half-Blood Prince when the movie is out since the book again comprises lots of trivials and events.  I'll just save it till the last one as Book 7 has returned to the ONE big mission formula and it's the finale anyway.