Screw open plan offices.
They suck in all ways.
The ideal office plan has individual real offices for each developer -walls all the way to the ceiling, real closing door, etc.
Each cluster of 3-7 offices opens onto a common space with a few tables and whiteboards for group work, etc.
Several clusters all share a common kitchen space, where at least once a week there is a company-paid lunch. Access to the cluster space is only through this common space, so you can get the (limited) benefit of people mingling for "collaboration", and the common free lunch means people will see other groups from time to time, and trigger any serendipitous synergies.
Adjustable sit/stand desks in each office, at least 2 large whiteboards in each office (Minimum 10x10 ft space). Two or more monitors, wireless mouse and kayboard.
