I sometimes still use
C-x r w <register> to store a window configuration in a register, and
C-x r j <register> (where
<register> is a single character) to jump back to it.
While this is a nice way for storing a few window configurations which you want to go back to after some time, I find winner-mode to be more convenient in a few regards. (For example, you won't have to bother naming the configurations).
(winner-mode 1) in your .emacs, bind
winner-redo to convenient shortcuts (or use the IMHO awkward
C-c <left> and
C-c <right> predefined ones), and you'll be able to switch back to previous window configurations.
M-: (info "(emacs) Window Convenience") and
M-: (info "(emacs) RegConfig")