I would paint the entire fireplace including the mantel, all trim and shelving white. I like the Whisper White, but you must bring the paint samples into the room to see for yourself. The sheen on all woodwork should be semi-gloss, easy cleaning and looks crisp. I agree with painting the walls and I would paint the part above the mantel the same color as the walls, Summer Hue is beautiful, but once again I have no idea how that would look in your room. The walls should be flat most brands make a fairly easy to clean flat. If the fireplace were the focal point of the room, it could look very cool and dramatic to paint it a very dark gray almost black. But at least in this picture it seems that the entertainment/shelving unit is the focal point. hmm .... better stop while I am ahead.

Have you ever thought about floating shelves? I think pairing a few floating shelves together would look great and would free up space in your living room. I really like the Eugene floating shelf from Bryght and I think it would compliment your existing pieces. http://www.bryght.com/product/160/eugene-cocoa-shelf

Firstly, one can play a lot with furnishings if you are staying in a rented apartment. those white walls are nothing but a clean canvas and you can really use colors through your furnishings like cushions , upholstery, curtains , rugs etc to add colors . Secondly , instead of wall shelves etc add small side tables on emptycorners you get etc which gives you platform surfaces to display your nick knacks.. You get many freestanding display shelves online and in market where you don't have to use screws in wall. :)

Well as it turns out, the sofa color is more like the 2nd picture (entire sofa), having seen it for the first time today. And I bought it, it is in fantastic shape, and am a bit excited about getting such a nice sofa. It is very comfortable too. So now we have to figure out how to lighten up that room!