Our den is pretty small and cluttered, we need a proper computer desk and bookshelves, here is what I have in mind.
   Now that you have an idea from the video, I will take you through each section in more detail. There will be five sections. Left bookshelf, Window Shelf, Upper Desk, Lower Desk, and Right Bookshelf(over TV).

   I intend to use cabinet grade birch 3/4" plywood from Fine Lumber (The owner is a friend of mine).

   The Left bookshelf is pretty straight forward design, similar to most any bookshelf from the store. Free standing, but anchored at the top to the wall. 3/4" sides and shelves with 1/4" backing. The side triangles will be datto'ed into the side and supported by the brace along the wall.

   The window shelf is a simple piece of 3/4" ply supported on each end where it attaches to the left shelf and upper desk, in the same way as the corner shelf.
   The Upper Desk and Lower Desk are separate pieces. I may move the shelves around a bit more, maybe add a cabinet. The upper desk will be 3/4" ply sides and shelves and 1/4" ply back along the walls. I think I should add an anchor piece under each shelf so I can screw it to the wall. If I did this I wouldn't need the 1/4" back, just leave the wall exposed. I'll have to see what Sherlyn thinks of this idea. Another idea is to add a couple of vertical 'sides' in the corner. One cool thing about this program is that in a few minutes I can mock each idea up to see how they look. I think the horizontal one looks better. In the image below you can see each idea represented. The upper shelf has the vertical supports, the lower shelf has the horizontal supports, with the left side open to the wall and the right covered with 1/4" plywood.

   After making these changes to the upper desk I have made a few of similar changes to the lower desk. If I did put a back piece against the wall, could I remove the left side panel, changing it to a diagonal support. Modifying this piece would open up the underside of the desk a lot and make it easier to access the front of the computers. I don't think doing the same to the other side would work as well and it wouldn't gain much since that area is covered by the TV stand.
   I still have a couple of problems with the right shelf. First is that I haven't figured out a good way of supporting this one. I intend each shelf to be movable. This leaves the top and bottom as the only places to add a an anchor piece. I also wonder if, due to location above the TV and weight of being full of books it should not just hang off the wall but have supports to the floor. I could extend the sides to the floor but this would reduce air circulation behind the TV and among other reasons, I think it would look funny.

   Another problem I have with this section is the size and location. The left end of the shelf is flush with the left edge of the TV, flush with the edge of the desk. The right end of the shelf is flush (w/ 1" clearance) with the edge of the door but 2" left of the edge of the TV. Since the TV sticks out away from the wall and the swing of the door, the door actually sits behind the TV when it is open. So... The bookshelf is not centered above the TV. I cannot move the right edge of the shelf right because of the door and I cannot move the left edge left because the desk is there. I don't want to move the left edge right (making the shelf narrower) since this would leave a 2" gap between this shelf and the upper desk.

   Also in the current design, the left side of the shelf is the same 3/4" ply as the right side of the upper desk. I don't think this would work. The obvious simple answer is to add another piece of 3/4" ply to be the left side panel of the right shelf. But this would show 1.5" of wood where the upper desk and right shelf meet. I think this would also look bad.