Click through to enlarge.
Here's the default wallpaper, the same one that is behind the login screen, and the default GTK theme and icons, Ambience and Ubuntu-Mono-Dark. The Unity desktop replaced Gnome for this release. On the top you have the panel, which looks the same, but is not a Gnome panel. Panel applets don't run in it; what you see on the left are all indicator applets, which have a much stricter set of guidelines for developers, apparently? On the left you have the launcher, which functions as a combined taskbar and application launcher. You can add, remove, and reorder the launchers on it at will except for the bottom ones (Trash, mounted volumes, Files and Folders, Applications, and the Workplace Switcher). The background is non-configurable atm, but you can resize it. It displays whatever icon theme is selected for the system and individual icons are still non-configurable. You can, however, turn on and off the background glow. The top panel can be made more or less transparent but not skinned independently of the GTK theme yet. Its transparency settings do not affect the launcher.
The search/shortcut menu that appears when you click the OS logo/start button in the upper left corner
The applications menu that appears when you click the search apps icon on the launcher. Those weird rendering errors that show up in the screenshot weren't there when looking at the screen. Must be a Shutter glitch.
This happens when you click the launcher icon of an application that already has multiple running instances open. (If only one is running, it simply rises to focus.)
The new "Me Menu" lets you set your chat status, configure your chat and microblogging (Twitter/Facebook/that open source imitator) accounts, and Tweet from the menu.
The messaging menu launches chat, email, and microblogging programs and notifies you of new messages. You can also apparently back up your data to the cloud from here (that's what Ubuntu One is, but I haven't set an account up).
The title and menubar are both integrated with the panel, which displays the title of the active window by default and the menu on hover.
This is how the Unity launcher handles overflow icons. First they tilt sideways at the bottom and sort of fold up away from you, but if you put the cursor over it the hovered icons comes back to focus/full size and some of the icons disappear off the top or the bottom of the launcher.