First of all, WOW! I am always astounded how people can come up with such great stuff.
Now:
Jarrett Lee wrote...
There's some amazing stuff here guys, seriously. Some of it is stunning. I particularly like the really clean N7 stuff for a CE for example.
It's super challenging to do box art that appeals to both the core fans and to potential new fans (we really do have to try to get more people into the franchise, that's our job). So for ME2, I know the regular edition art was pretty polarizing, but the N7 CE (made for the core fans) was very popular 
one thing the excercise in this thread shows: ME3 is many things to many people, so it will be hard to hit the sweet spot....
I am all for that. Make a fancy colorful cover for the regular edition on the shelves and give us (the hardcore fans) an amazing unusual collector/ N7 edition.
I also really like the idea of the clean N7 cover art. For ME2 we had the rather dirty N7 edition (which fitted well). Now for ME3, we need some contrast and the sleek and clean art design that is so abundend in the ME universe calls for a very minimalistic but stylish cover art IMO.