This totally depends on the size and shape of the space, plus what it needs to include. General advice is to always create zones within the room, subtly dividing it up based on purpose. If your room is large enough, and you can still easily move around the space, furniture is a good way to do this - use pieces a bit like walls to create pathways through the space that separate different areas. Rugs work well for this too.
Be sure to also pick a focal point of the room and allow that to dictate your layout. That might be the TV, a feature wall, or a fireplace, this will give your layout a bit of structure despite probably having lots of different functions going on.