The Linux Penguin

Until Linus starting using the Penguin as a symbol, all the images around Unix were a wizard.  This required people to explain that Unix was so completely complicated that only wizards understood it.  The perception of the "Unix Wizard" eventually became more of a hindrance than a badge of pride.  It was brilliant for Linus to adopt the Penguin, which is friendly, cute, and cuddly.  Changing the symbol from a Wizard to a Penguin may have done more for the marketing of *nix systems than years of corporate efforts by AT&T/USL, HP, Sun, and so on.