I thought about getting 3 screens, but went for 2 big ones (2560 x 1440) instead. Not great quality ones since I mostly view text, not games or movies.
I think at this point it's easier to press a hotkey to show another workspace on the screen, than it is to turn my head. But who knows, maybe one day.
My non-programmer friend has two screens, but keeps turning one off to watch videos or to not lose the mouse. It's hard for me to imagine that anyone would do that... If my crappy GPU supported it, I'd steal one screen.
I really dislike working on laptops, but that's as much about the screen as the keyboard and mouse.