The best setup I think I've ever seen was a large room with tiny personal cubicles lining the walls, and islands of open work areas in the center. You could go to your cubelet for phone calls, email, storing your coat, etc, but coding work was done at the islands. Each island consisted of five workstations two on each side and one at one end. Each workstation had two 24" monitors and a wide berth, with two chairs and more available. Pair programming was comfy, and getting four or five people around a single piece of work was easy.

If you were at the islands, you were working and available to be called over. If you were in your private cubicle, you were to be left alone unless it was really important. From total openness to decent privacy in a few steps. That's as good a balance as I've seen.