A fireplace is just a feature if there isn't a stocky chimney breast to make it stand proud. If you've been looking carefully you will have noticed that the left chimney on this house isn't well placed: it lines up with the staircase. That's been bugging me for a while and its something I'll be looking out for with my next house.
I've built a chimney breast tonight out of strong card. It will be wallpapered as part of the main wall. One of the photos below looks remarkably realistic.