Earlier quoted context omitted.
At work, my widescreen monitor is perfect for showing two columns of code on the screen. That may be a reflection on the cleanliness of our codebase though...
Are you using an IDE that has sidebars or other elements on the screen than code? In my setup with Emacs, a 1600x1200 screen and 12px monospaced font, I have two 86 character wide windows side by side. To add another column without changing something else, I would need a 2400px wide screen. I wouldn't object to a large 2:1 aspect screen on my desktop, but it makes for an unwieldy shape for a laptop.
I'm not at work right now, but from memory I get around 120 characters in each column without any sidebars.