I prefer to work with a single large external monitor. If my device is a laptop I keep it in clamshell mode when attached to an external monitor. I find switching applications with keyboard shortcuts and focusing on one thing at a time has improved my productivity. Using two or more monitors made it so easy for me to get distracted. To each their own though.
Everything else lives on my 32" 4K monitor. This gets me a nice compromise, as I found having two larger monitors leading to distraction as well (or just completely ignoring one of the monitors, so it added little value to me).