You can put up shelves in the middle of an open space. I've done that before to divide a finished basement room into "office" and "bedroom" sections. I'm a big

You can put up shelves in the middle of an open space. I've done that before to divide a finished basement room into "office" and "bedroom" sections. I'm a big fan of double-sided shelves like the Ikea Expedit/Kallax lines, but anything will do. Open space gives you the option of dividing it up as you like. A fixed wall makes the decision for you.