New Finder Window
Tip: to open a new Finder-window, tab to the Finder-icon in the application switcher, hold the Cmd-key, press the Alt-key, release Cmd-key.
An obscure, unconventional command key combo. I’m not sure it’s any quicker than switching to the Finder and whacking ⌘ + N, but it’s nice to know it’s there!
@keyboardkitteh reports that the trick ‘works with any app that has no currently open windows, not just Finder’. Let the muscle memory re-training begin.
@asheidan points out that the shortcut ‘also works to unminimize minimized windows’.
@jeffunity offers another handy command key combo: ⌘ + ⌥ + Space, which opens a new Finder window with the search bar in focus.