Last month, Marvel announced that they’ll be releasing a 10-disc, six-movie Blu-ray collector’s set called Marvel Cinematic Universe: Phase One – Avengers Assembled.  The ginormous set will include all of Marvel’s films up through The Avengers, as well as loads of special features.  Now Marvel has released some truly gorgeous box art for the set, as Matthew Ferguson has cooked up some fantastic sleeves to go with each corresponding movie.  The sleeves will house each individual movie, while the actual box for the whole set looks like it’ll be in the shape of a briefcase.Hit the jump to check out the images, and begin the debates over which one’s the best.  Marvel Cinematic Universe: Phase One – Avengers Assembled will hit stores on September 25th.Here's a trailer for the set, followed by the images (via Marvel).  You can also pre-order the set right now on Amazon.