This is a really awkward space! What about trying to build a unit into the corner which seems to be dead space. This could house the television and other bits like dvr,amp etc. The unit could then extend out towards the door in length and in height either up to the start of the window or up to the start of the blinds. I would suggest drawers for toy storage and books above. In this way you leave the windows clear for light plus it looks like you have a pull down screen so the tv would be out of the way of that. This arrangement would also hide all those wires and cables! Ikea have some good examples of storage which you could adapt or copy, such as Besta which illustrates the extended toy storage. http://www.ikea.com/gb/en/catalog/products/S39927155/

I would wait for the rug, until you have the shutters up and your furniture placed..it may take on a character of its own and you'll want to compliment. My first thought though was to coordinate with your kitchen and incorporate some black, with a black/beige stripped rug, which would be fun with the wallpaper and perhaps paint your chairs black, add the shutters and you could paint the window trim black and add a large black chandelier.

How about some stunning black wall sconce lights along the wall? Here's a very contemporary example... The soft grey is an excellent option, and will look stunning with green foliage against it. To give it a real 'look' I'd suggest installing some kind of black feature - whether this be painting the window frame & putting shutters either side, or the sconce lights, or a modern metal artwork. Perhaps even tall black plant pots either side of the window.

Well that is an interesting picture. I can assure you that hanging wall gardens are all the rage and that is a great idea but they can also be high maintenance if exposed to high winds / sunshine etc. I have seen some lovely fake ones that would do just as well. You could also have a few pots with additional greenery. As you say your view is not "great" maybe you can have a creeper in one of the pots that can weave its way through the railing. I probably wouldn't go for one big chair as it could dominate the entire space. I would consider a table with a couple of fold-able chairs .... something that is comfortable, inviting if you have friends over but can be placed in a corner if you just want to open up the space. I do not think you need a carpet and but maybe some fancy outdoor tiles will look just as nice. You want it to be easy care and weather proof. Do you need or wish to incorporate a washing line? A pull out one from a wall will be perfect that way you can retract it back when you are not using it. If you deck gets too much sun, you may want to consider some shade shutters. I have seen them called 'plantation' shutters. GOOD LUCK