I agree that for most tasks, mastering virtual desktops is superior to having your work spread out through multiple monitors. These days, my extra monitor is just gathering dust.
But, you have to admit that for some tasks, the extra monitor is useful:
- Having your developer console at the tilt of the eye
- Keeping an eye on some background task running in a console
- Having a browser in “CSS auto-refresh” while tweaking visuals
I feel that quickly looking down and back up feels more natural than looking right then back left.