Interesting shot, I like it. Nice composition. It seems to be a little soft. I don't think I would have used noise reduction on this one. B/W photos can stand to have a little edge and grain in them, it give them a feel of there own. If you didn't use NR and camera shots a little soft, I might have used Unsharp Mask to give it some bite. Great idea.
This is a newsy item, but I think your photo tells rather than shows. Perhaps if you'd included interested bookstore customers or an individual reacting to the display. As is, it simply documents a store display. Vertical lines need to be straightened and the inclusion of the angled side of the bookshelf gives the feeling that it might fall over.
This is tough - because I suspect people would prefer a tighter closeup of the president than all this - it seems to busy to be "reflecting" or "mourning". Also - the angle is a little distracting. Good concept though.
I can't see what you are trying to show in this picture. Is it the arrangement of the books or the contents of the front cover? In either case it's a bad example.