Agree with carrieandjimh, You will need to connect the two colors through prints on pillows, curtains, rug etc. Can you post a pic of the sofa and wall color so we can see what we're talking about here? Thx.

You may use a specific light in the grey on the wall were there are two windows. While the other wall with a long slim window has a wall feature design. There are numerous features to use, with the intension that it would be on the same colour contrast. As was mentioned that the blinds would be great sprayed though in a colour that will go with the walls colour and design. Need to be a balance in the colours for both walls and the blinds. You may use one wall with wallpaper feature if you prefer. I have found a site that may assist you with the design of your choice. http://colorhunter.com/; http://www.resene.com.au/wallpaper/#

As said by big reader...leave white or paint the same colour, without the brushed finish, on the other walls. You can not bring another colour in. There is enough colour already with the orange wood and the bed cover. Also, the curtains look too small to pull right across your window correctly. They should be waved not flat when closed.

I agree with Jan -- a lot is personal , and your lifestyles . You say neutral colours , so a wheat type colour for the carpet is a good middle of the road choice , but maybe not practical with kids who like crayons and facepainting and stripping down motorbikes haha . So in that case , maybe a burgundy or mid blue or similar 'solid' colour may suit better ( burgundy may tie in more with the exterior tones ) , but is still sort of neutral , but what about furniture and linen and artwork -- if you have royal blue or fluro green drawers and a brown chair and sunshine yellow duvet/dooner cover , and the room is for someone older than 4 , then burgundy carpet mightn't be the go haha . The existing wall colour works with most things , you can add artwork or posters or sports or academic certificates -- maybe back to front , but I'd sort out everything else ( carpet , furniture , etc ) before deciding on a wall colour , unless sticking to the existing or similar colour .