i have a room just about that size and use it for sewing/computer/tv room.
hubby built floor to ceiling shelves on two of the walls which hold an enormous amount of storage boxes.
I have a corner desk which holds Tv and computer and has two small bookcases on each side for printer and books (or wahtever!!)
he also built me a table 20"x42" with 2- 26" drop leaves. (opened-72"x42)
To be truthful, I don't open it to it's entirety too often, hard to maneuver around it....but it is helpful when pinning a large item.
I have one closet in the room which stores fabric.
Works for me.....