I couldn't possibly go back to a single monitor again. Both at home and at work, I use a dual 24" monitor setup. 1920x1080 at work, 1920x1200 at home.
It allows you to full screen one app and use another thing such as a web browser on the 2nd. I can also drag my materials box and anything else over there so it's out of the way of my main window.
Only problem is now that when I use my laptop, I find it really hard to adjust back to the single screen.