Browsing the Gnome Shell wiki @ live.gnome.org, I stumbled upon some great login screen and lock screen mockups which you can view below:

Right now you have multiple desktops but only from the applications point of view: you can move applications from one desktop to another and that's it. There is currently a mockup posted @ Gnome Shell Design Playground website (and a lot of discussion about it on the Gnome Shell mailing list) which seems very interesting:

Fish is a user friendly command line shell. It features syntax highlighting, advanced tab completion features, discoverable help, a revised shell syntax and many other features.

Fish comes with a lot of features, but I find one feature truly amazing: tab completion for command line arguments, including explanations.

Here are the fist (probably the first ever) 5 Gnome Shell Themes (download link at the end of the post):

Marine Gnome Shell Theme:

Gnome Shell is the new core user interface for Gnome 3 which provides switching windows and applications but you've probably already heard of it by now so I'll skip the introduction.

This repository contains the following packages:

-Docky (version 2.0~bzr315-0 at the time of writing this post) - the dock bar part of Gnome Do (read on!)