Operating System Interface Design Between 1981 and 2009

"Intuitive user interfaces often use metaphor as an effective 'vehicle of exploration', according to David Siegel in Creating Killer Websites. His examples of metaphors include: 'galleries, TV remote controls, magazines, tabloids, store environments, museums, postcard racks, amusement pars, going inside things (computers, human body, buildings, ant farm, and so on), safaris, cities, and cupboards."

-David Whitbread in The Design Manual

Also... check out Microsoft Bob.

It seems like the analog clock widget is the perennial "Hello World" of slightly more advanced GUI applications. Anyone can implement it (no spec required), it's somewhat fun to write, and it works as a test for some of the more essential APIs in a GUI operating system such as vector graphics and timer events.

I think there's also a psychological aspect involved. The analog clock may be popular precisely because it's inefficient in the ways you described. Including it in a computer operating system may be an attempt to communicate that the system's designers want to respect traditional GUI values like user-centric design and real-world metaphors; that it's the kind of system where they don't mind spending CPU cycles on an inefficient information element as long as it breaks the monotony of text-based interfaces and offers a small tinge of familiarity. (The analog clock is something that you wouldn't find on a 1984 IBM system.)

Gnome is there, although they don't have a recent version.

Ubuntu didn't do anything too incredible (GUI-wise). They just themed gnome. It's pretty, but there are so many more notable GUIs for linux.