The punchline:
> The monthly rent for our offices, when fully occupied, will run about $700 per employee.
That's $8,400 per year in Manhattan.
This appears to be their new office space: http://www.businessinsider.com.au/stack-exchange-office-tour...
And these are shots from their new Denver office: http://www.flickr.com/photos/stackexchange/7776308984/in/set... http://blog.stackoverflow.com/2012/09/join-us-for-our-openin...
tl;dr there is at least some open-plan stuff. Which, really, just makes the most sense; a healthy mix of options is hard to argue with.
I thought the "light on two sides" was particularly clever.
One thing holding back enclosed offices in SF is the very high ceilings in many of the older buildings. would high walled cubes work?