I have three monitors and my desktop is too crowed. Last year in the middle of tax season, because of the 2012 ATX problems, I bought another screaming fast computer and just loaded ATX to get through the season. Only program on it at the time.
My original computer was and still is fine for our other applications, and partly because of licensing our software, I still have both computers and three monitors. I tried a keyboard splitter, but that was tedious, so you can imagine how much desk area is devoted to technology.
I'm used to it now, and not sure I would go back.