Hanging beautiful plates on a wall could be an inexpensive way to fill up that empty space you've been staring at. We have a few in our home still and I can't keep putting up gallery walls everywhere. The only reason I haven't really considered it until now is that we are always throwing a toy for Tater in the den. So maybe upstairs could be an option.
You could hang your favorite collection, or find great deals on random assortments at the flea market. Here is a great how to that you could try!