Stone building interiors

Some of the more "upper class" stone housing should have feature rooms which have ornate wood panelling. This helps the rooms feel more light, and were easier for the owners to decorate themselves. It would also help insulate the rooms, so you'd expect to see this in the rooms where the inhabitants spend a lot of time. As Richard will agree, they also hide secret doors rather well!

Empty "shields" onto which custom heraldry could be put would also give a wonderful medieval feel.

Some examples of wooden panelling from the College of Arms in London. http://catsgopurr.com/SOTA/IMG_1946.JPG http://catsgopurr.com/SOTA/IMG_1947.JPG