Home screen bottom bar buttons I don't understand why the Android 2.3 SDK docs show the home screen dock as beeing this:
http://upload.wikimedia.org/wikipedia/commons/f/fc/Google_Nexus_S_smartphone.jpg

And I have this, unchanged from 2.1 to 2.3.4 now:
http://blog.nimbuzz.com/files/2010/06/samsung-galaxy-s-android-launches-2.jpg

Is it a Samsung thing?
Is there an official launcher for 2.3 and the Samsung one?

Thank you.
Basically, yes. That's Samsung's UI/framework, TouchWiz. Other manufacturers have their own UIs as well, including HTC's Sense and Motorola's Motoblur. The Nexus S has the "stock" Android UI.