Personnaly I have never been a fan of the Mac OS X look or the liquid theme. I must be one of the rare person who has happy that the new default theme for KDE is Keramic and not liquid. But, many poeple say that the Mac OS X is the nicest looking OS, so it must be pretty in some ways which my mind cannot grasp.
Well..I think it´s good for everyone to have the possibility to "emulate" the look of an existing OS. This makes it very easy for someone who just switched. On the other hand, I agree that this shouldn´t be the only solution. But since KDE is VERY costumizable, who cares?