That's not what I do, because it doesn't make sense. Text that takes up the entire width of the monitor is either in an unreadably long line, or in unpleasantly large text. There's only so much margin you can handle on either side of the text before it just looks silly. And I don't think multi-column is the way sites should or are going - it interacts poorly with scrolling.
Thus I don't use maximized browser windows on big monitors. I use tree-style tabs, which uses a bunch of horizontal browser space much more productively than big margins, and I cascade my browser window with other windows so I can easily switch windows using the lower left corner of each window. With it occupying the rightmost and tallest position in the cascade, it is further reduced in horizontal size.
tl;dr: Web browsing, being primarily a text medium, doesn't scale up to wider and wider monitors. So don't make the window so wide.
But to show what I'm talking about, here's how the page looks on my desktop in Chrome:
Again, that just seems like wasted real-estate.