Shakespeare said, “a rose by any other name would smell as sweet.” That may be true (although Bart Simpson once quipped, “not if you called them stink blossoms” and he may have a point). But what about visual identities? Would Batman be the same if it was done ala South Park? Or, for something a bit closer to home, would Ubuntu be the same if it looked like OSX? Sure, it would likely run the same, but would our reaction to it, and the reaction of newcomers, be the same?
I’ve read plenty of arguments for and against the human theme, but regardless of your feelings towards a brown desktop (although aren’t most desks brownish?) you have to admit that it is unique.