You don't need something on every inch of wall space. You already have this console table ensemble to welcome you in the door -- I'd leave that other space free until such a time as something just jumps out and grabs you. The walls look pretty neat!

First, I would recommend changing all the switch plates to brushed nickel or stainless. Most hardware stores carry these.

Second, for a wall feature that doesn't stick out like shelves, you might want to take a look at our product. We can print any image or graphic that you like, including a matte black graphic on a shiny black background (the same can be done with white). We then install the membrane by inserting the edges into a track that we mount on the wall all around the perimeter. The tracks stick out less than one inch. We can also place LED lighting behind a mural printed on translucent membrane, but that does stick out a bit more.

I always think that these wall climbing men are fun http://www.ironaccents.com/29-880849.html or you could hang art that you like, something long and rectangular or a block of 4 smaller square framed photos or paintings...
Maybe something like this? http://www.gallerydirect.com/art/product/judy-paul/tall-and-skinny?substrate=canvas&style=CG&frame=F0000&size=XL

I'd suggest a contemporary chrome floor clock - here's one from Herman Miller. I believe they make this style in two sizes.
http://www.howardmiller.com/ProductDisplay?catalogId=13551&storeId=12652&productId=3166498&langId=-1&categoryId=36152&parent_category_rn=36152&top_category=