I don't think I run anything full-screen. I am irked by not being able to see the other things I need while working (files, time tracking, notes, email, FTP, etc). But maybe it depends on whether you have a single screen or more than one? I have four displays (MacBook Pro plus externals: 34" curved, 26" landscape, 26" portrait) and 14 different app windows currently visible in one way or another. I feel very cramped if I use the laptop on its own.

how big is your monitor ? When I am on my laptop I run everything full screen. When I am on my desktop I have two 20" monitors and I regularly have multiple windows open on each. I have found that splitting vertically on one monitor with the code I am actively working on and firefox for looking up things works really well for me.

I have a 27" monitor, and 90% of the time, it shows a single maximized app, with the browser second in the Alt+Tab stack (so you can switch back and forth just pressing it once).

Does that not make for either a lot of wasted space, or ridiculously wide text?

For the browser, it does (wasted horizontal space), but you can also rephrase it as "less distraction".

Most productivity apps, however, have their own way to subdivide space within the app efficiently. E.g. in the IDE, there are various panes and tool windows. Put a file browser on one side, a documentation browser on the other, and a terminal pane on the bottom, and it actually starts feeling kinda crowded.

This guy is either trolling or he's the UX designer behind Windows 8

Either way he should be ashamed of himself!

Doing exactly this with a tiling windows manager was a game-changer for me, and I can't imagine going back to an "Alt-Tab" environment.