Concrete has always had such a bad press, particularly in the UK, where it's usually uttered in the same breath as "monstrous carbuncle". I would agree that images of rain streaked grey and soulless housing estates don't help its cause, but there is another side, as exemplified by the work of the great Japanese architect, Tadao Ando, for example. His 'church of the light' is possibly one of the simplest and most sublime structures on the planet. Concrete is also surprisingly varied. At the opposite end of the spectrum from Ando's smooth finishes, there are any number of rugged textures that can be employed. This was particularly popular in the 'Brutalism' of the 60s and 70s. My own particular favourite being the hand chiseled columns of London's Barbican. (Ref. example in earlier post. Apologies, you need to scroll down quite a bit!)
The simple modern extension I photographed recently for Architects, MAP Projects, showed how a sleek white living space, with splashes of vibrant colour, could be given added depth by the addition of a raw concrete exterior wall. The wall forms the property's boundary, and is seen through the full height glazing which runs down much of one side of the extension.