Probably the cubicle. It doesn't seem as lonely as the private office but gives enough privacy one can more easily have a meeting with the remote/out-of-office people, to pick your nose, or to get work done without people constantly passing by you. Sadly they look like remnants of the past since everyone seems to do the open plan.
Cubicle with walls moved by hydraulic pistons to make your cubicle bigger when you exceed your quota. If you don't, they start to close in, Star Wars trash-compactor style.