Simon Long is the user interface guru at the Raspberry Pi Foundation and is the one responsible for the desktop updates featured in the new Raspbian. He’s written about some of the process he went through to improve the desktop and has listed many of the new features here, on the Raspberry Pi blog. He’s also described how to change the position of that pesky task bar/start menu if you’d like it returned to the bottom of the screen (thus neatly side-stepping the argument about whether it should be at the top or the bottom).
To get the new desktop, you can either use the new version of NOOBS or Raspbian, or alternatively type the following into an existing installation.
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install raspberrypi-ui-mods