I wouldn't want less than two
But I work from home now and they are gung ho on getting me on company issued hardware
so I'm working with 3 currently
I usually have email, a browser window or two, and my IDE, and any other supporting tools all up at any given moment
So the third monitor is usually just so I can keep an eye on incoming requests
which if I have to rely on watching my taskbar and listening for the ding thats ok
which is why I'd settle for 2 monitors
I have one monitor in the office and its just painful :(
As far as picking the system go
I do some traveling and they are looking to decomission the two PCs I have sitting in the office that I currently VPN / RDP into as needed
and since I travel to the office and clients sometimes I am probably looking at a laptop of sorts
Most likely, the laptop will mostly act as a thin client and I'll RDP to Azure and / or a work virtual environment for serious tasks
thing is I don't want to just stare at a laptop monitor and I don't want to use the laptop keyboard and touchpad and I don't want to have to deal with a mess of wires between work and play. KVM seems like a reasonable solution which slipped my mind. Haven't thought of those since TechTV went off the air :D