The corners of Sub-d's can be creased to make them sharp, or partial crease for an "in-between". Partial crease is sometimes too soft, but if you refine the subdivision level and then partial crease it at the higher division then the crease will be sharper (eg. see the recent edges on the big gold bit of my sword).

Otherwise, poly's can be smoothed by clicking polygons>smooth poly's

PS. it might be easier to just bump-map the walls.