Most of the time, I run Emacs in a single, maximized frame (and, sometimes, just inside a urxvt terminal). Inside that frame i create and destroy windows as needed to contain my buffers . After a while working with Emacs one gets used to a fluid window setup, where windows come and go as need arises.
But I remember that in the early days I felt a bit confused: I started by creating a windows setup (split horizontally, then vertically, open files in each of the windows… that kind of thing) and was non-plussed when any operation (going to a Gnus buffer and reading messages, for instance) destroyed my carefully prepared layout. Over the years i’ve seen many a newbie feeling that way. My advice is usually to let go, and learn how to move around your windows, creating them as needed.
That said, i must admit that, sometimes, i want to recover a certain window configuration in a quick way. A particularly simple one is provided by
winner-mode, a package which is part of Emacs. Winner keeps track of your window configurations, and provides functions to navigate your window configuration history.
As advertised, activating
winner-mode (which is a global minor mode) is as easy as one can get: just type
M-x winner-mode or put this line:
in your .emacs. Use Emacs normally, and whenever one cherished window layout gets destroyed, press
C-c <left> (where <left> refers to the left cursor key) to recover it–actually, this calls
winner-undo, and you can invoke it as many times as you want to visit previous window configurations. As one would expect,
C-c <right> (the default binding for
winner-redo) navigates configurations in the opposite direction . Simple and very useful, as it should be.
But maybe you want to be automatically tele-transported to a previous configuration without traversing the intermediate ones. No problem: Emacs provides functions to store and retrieve window configurations (which, in fact, are the ones
winner-mode is using under the covers). You can store the current window configuration in register ‘a’ (registers are named using single letters or numbers) pressing
C-x r w a, and restore it later by means of
C-x r j a. Again, it’s that easy.
Although there exist several packages providing more sophisticated window management (named configs, save and restore, etc.), in my experience, the simple tricks described above are more than enough (and work out of the box in any Emacs). As always, YMMV.
 For those of you not familiar with Emacs lingo, an Emacs frame is what most window managers would call a window, while an Emacs window is any of the regions displaying a buffer inside a frame. Usual ways of creating windows in Emacs are
C-x 4 f, and so on. See Windows and WindowsAndFrames for more.
 In Emacs 21, the default keybindings start with
C-x instead of