Finnish Fireplaces

http://www.woodmasonry.com/pages/whatis.html

Highly effecient and ornamental at the same time. The firebox is placed within a chamber that forces the exhuast gasses to flow through winding channels of thermal mass. The heat is stored in the thermal mass and then radiated out even after the fire has stopped burning.

Expensive, but they can look very nice and they can potentially meet (or exceed?) effeciency numbers for even catalytic burn fireplaces.