Another Snow Leopard Tip: Option-Click Sound menu and get input/output options
9to5mac.com/2009/09/02/another-snow-leopard-tip-option-click-sound-menu-and-get-inputoutput-options
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
David Pogue tweets (update: MacOSXHints had it yesterday) a pretty cool little tip for those of you whove upgraded to Snow Leopard: <Option-clicking> on the sound menu item at the top of the screen allows you to quickly change your sound input and output options.