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/

The first thing I see is that the stuff on the wall to the right of the window could be arranged better. Maybe a more appropriate sized piece of furniture in the corner might help :-)

squeakerd - it is really hard to get a perspective on the whole area but if this is part of a much larger area then I feel you need to first decide just what you want as the end result. Do you just want your entire area to be one open plan or do you want to break it down into visually defined areas within the open plan. As you have the area now, I don't feel any cohesiveness between your table and the sideboard, I think I would move the sideboard to the end wall, it looks more like it would belong there, even just by the shape of the room. Definitely a larger rug will define the space better - just be careful of any trip hazard with the door nearby - but before you decide on the rug, consider window dressings and whether you want things plain or introduce some bold patterns and what colours look best in the area. Artwork can go where your sideboard is now, but again think colours and impact of design on the whole area. It is all very well to build a room around one piece, but you need to look at the impact that piece will have on other items and what limitations it could cause. I would suggest you set aside some serious time to look through photos on Houzz, especially if you can find areas similar to yours, till you find what appeals to you, put the photos into your ideas book and use that to build your room. I have found this invaluable in the past and it has saved me many an expensive mistake.

You could reverse the layout of the ensuite, and have the door to it through the walk in wardrobe (so you would only have one door coming off the bedroom). If I were you, I'd consider swapping the positions of the ensuite and wardrobe, so the current ensuite door becomes the wardrobe door. That way you could move the bed to the east (right), and you would have room for a seating area in the north west corner of the room (as your bedroom looks huge!). I'd also add a window on the small bit of north facing wall in that room; you already have corner windows in the living and another bedroom, so you could match those in style. Personally I don't particularly like the current layout of the main bathroom, although I can see the reasoning behind it (i.e. vanity at entrance, toilet hidden behind wall, window above bath). I think it might work better if you put the shower in the corner where the bath currently is (i.e. beside the toilet, opening to the west), and the bath on the same wall as the vanity. You'd have to move the window, of course. Alternatively, do you actually need three toilets? You could remove the toilet in the main bathroom, and you'd have room for a freestanding bath and/or a bigger shower. You could consider stealing a bit of space from the kitchen to create some storage at the entryway. I'm not sure where your garage will be, but it's really handy to have a designated place at the point of entry for all the stuff you tend to dump when you first come into the house (schoolbags, coats, mail etc). Overall, I think the layout is pretty good, but you could potentially lower the build cost by making it all a bit smaller. It's really worthwhile taking the time to figure out just how much space you actually need, and where you need it. For example, if it were my house, I'd take about half a metre off both the east bedrooms (so the house is shorter from east to west), plus I'd make it smaller north to south by slightly reducing the size of all three bedrooms, and making the kitchen a bit smaller (so the hall cupboard lines up with the back wall of the small living room). But your priorities may be completely different from mine!