I don't know how it is for other people, but around here if there is room with out a purpose, it quickly becomes what can only be called a 'junk room'. Just like junk drawers in the kitchen, a 'junk room' quickly takes over your life and you will never find anything. Construction tools, empty paint cans, ladders, boxes we might need, Christmas decorations that are too large to fit in the closet, camping gear, junk mail, newspapers. All have resided at one time or another in one junk room or another. In order to stop random formation junk rooms, any spare rooms, are given a dedicated purpose, and are decorated to ensure that no more junk accumulation will happen. It doesn't always work, but we do try.
About 5 years ago we dedicated one room as Mr. Needles study. Loosely translated it means that the computer is in here, along with Mr. Needles strictly personal types of junk that guys have. Mr. Needles collection of guy junk is actually fairly contained and well defined. It's all related to wildlife and fishing and hunting. The only problem with Mr. Needles study was that it was never finished.
The original plan was to build in cabinets so we didn't paint with the very expensive sand paint along one wall. A year or two after the fact (right when the sand paint colour we used was no longer produced) we decided to buy book cases which left us with a wall that did not match and a big problem. It took the wind right out of our sails. Renovation stopped, and the study was left hanging midway between elegant but manly space and junk room.
We solved the unpainted wall with a wall mural. It suits the character of the man, and his passions. For the last 3 years, the mural sat in a box on top of the book cases. Today it goes onto the wall.
Wish me luck.