It's starting to look very good, a couple of things you may want to look at.
Spine - I would change it around a bit. move the DVD and CC logo's down, move the Miramax logo to the top, move the title down more central and get rid of widescreen. Being as you have it on the front it isn't needed on the spine. Also it is only Universal that tend to display that way.
Back - I like very much, but I would redo your brush work behind the critic quote at the top. It is just a bit too heavy at the moment.
Front - I am wondering what it would look like with an image of the front of the palace, rather than the back. I think a lot of people would wonder what building it was, as it is a view that is seldom seen. It would also introduce a small amount of colour to the front that is needed IMO. It's not that bland in the UK (IMG:style_emoticons/default/winking.gif