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.
Having a 50" TV lets me sit pretty far away from the screen and also gives me plenty of room to put a million applications next to each other which (at least for me) helps me avoid being distracted. I also have a lot of issues reading small text [1], so having a big screen allows me to make the text gigantic while not sacrificing a ton of screen real estate.
It's honestly great; if I ever am forced to work in an office again, I'm going to insist that the company purchase me the equipment for a similar setup.
[1] I'm reasonably certain that I'm not dyslexic, but I do find that reading off a screen is substantially easier for me when I use extremely big text. This is part of the reason most my book reading is either on the Kindle or the large-print vision-impaired versions of books.