Well I'm only speaking out of personal experience, when I need focus I just need any old screen with fullscreen Emacs running on it, extra screen space just invites distractions. I'm probably a bit of an outlier there...
Depends how frequently you need documentation, and I do iOS so I'm typically running a large iPhone Simulator instance on screen as well.
I'll take quiet side room every time. I honestly question our need for giant monitors. The likes of Visual Studio is very wasteful of screen real estate.