I use a tiling window manager (spectrwm) and I am almost always using a single window in fullscreen. Apart from the browser most of my workspace exists inside the terminal where I'm very liberal with using multiple panes/windows/sessions in tmux. This fills a similiar role for me with regards to tiling, but for almost everything else I prefer having only a single application front-and-center at a time, with tiling available for rare occasions.

What I like about the tiling wm is that I can launch an application and have it immediately fill the entire screen (without annoying decorations). Then opening and closing windows, changing windows, moving workspaces, etc, is all just a hotkey away.

This same setup would be possible with openbox I think, but it all comes "out of the box" with most tiling window managers.