Very useful for stuff like whitespace-mode or auto-fill-mode:
whitespace-mode
auto-fill-mode
(hook 'c-mode-hook (lambda () (xxxxxxxx-mode -1))) (add-hook 'js-mode-hook (lambda () (xxxxxxxx-mode -1)))
If you are using Prelude you can just use C-c s (prelude-swap-windows). From the Prelude documentation:
C-c s
prelude-swap-windows
C-c s runs the command crux-swap-windows (found in prelude-mode-map), which is an alias for crux-transpose-windows in crux.el.
crux-swap-windows
prelude-mode-map
crux-transpose-windows