the_other parent
As someone who uses screen zoom tools constantly, I vote in favour of the 80ch column width recommendation. If you want to support extra wide monitors, consider using multiple columns, rather than a single, wider one.
Multiple columns don't really work with websites, as web content almost always going to be vertically scrollable.
Columns work great for things like a navigation sidebar or an image grid, but it just doesn't play nice with long-form blog content.
Fair, but neither do long line lengths.