well the default ubuntu setup with just GTK apps from the repos result in a quite decent consistent GUI setup. it just gets dog ugly when mixing QT apps.
I also prefer the OSX consistency, but lately things are changing with apple as well. perhaps for the OSX10.7 lion release with a new concept? I don't know but stuff like those horrible vertical itunes X controls make me shiver.
Hehe, I agree re: iTunes, I never got the hang of the UI.
I prefer VLC for media (movies) and use Spotify to play local music files - it has a great interface.