Seen over on Compendium (via MetaFilter), the OS gals. Of course, my favorite is the Mac OS X Gal.

A small internet phenomenon on Futaba Channel, the OS-tan (OS for Operating System, and -tan as an overly cute Japanese honorific for a person, specifically a child slurring "-chan") or simply OS Girls are the personification of several OSes, most famously Windows, by various amateur Japanese artists. A pure fan creation, the appearance of each character is generally consistent among artists. OSes are almost always portrayed as women, the Windows girls usually as sisters, despite sometimes seeming the same age.

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The Mac OS X girl is often portrayed as cat-eared, in following with the Apple "wild cat" naming tradition (every MacOS X release has a codename like "Jaguar", "Panther" and so on). Otherwise, she is shown as an older variation of the Mac OS 9 girl, wearing a platinum white coat and a wireless AirPort device fashioned as a hat. She is occasionally shown holding a newspaper or yearbook, as many high school newspapers and yearbooks use Mac OS X. [Wikipedia]

Too cute (or dare I say.... KAWAII!)