Here are some operating system inspired WordPress themes of varying style, quality and version compatibility:
22 Apple Inspired Free WordPress themes. Some more Apple inspired themes (including iPhone-styled ones, among others).
WordPress cli. The famous theme that turns your WP blog into a (functional, not just styled) command line interface one. Awesome stuff, but is likely to confuse new visitors.
From all the themes in this list, Leopress and Vistalicious would be my top choices. What about yours? Also, do let us know if you know more great themes that belong to this collection!