Please note that this is not a desktop shell replacement, as you are just using the Windows task bar.
The background is a simple gradient with a stock image centered.
As for the clock and other info in the upper right corner, that's a custom version of Rainmeter Enigma:
You can get Rainmeter, which comes with the above theme.
Rainmeter is a desktop customization platform. Through Rainmeter, you can enhance your Windows computer at home or work with skins: handy, compact applets which float freely on your desktop, much like Windows Sidebar gagdgets, or dashboard widgets for the Mac. Rainmeter skins provide you with useful information at a glance. It's easy to keep an eye on your system resources, like memory and battery power, or your online data streams, including email, RSS feeds, and weather forecasts. Many skins are even functional: they can record your notes and to-do lists, launch your favorite applications, and send your tweets to Twitter - all in a clean, unobtrusive interface that you can rearrange and customize to your liking.
The icons you see beneath the image are an ObjectDock.
ObjectDock is a dock similar to that in the Aqua GUI. It is distributed by Stardock for Windows 2000, 2003, XP, Vista and 7, and comes in Free and Plus versions. It allows the user to place shortcuts to any program in a "dock." This provides Windows users functionality similar to that of Mac OS X. The program comes in two versions, free, and a paid version offering more features. Both are available at their official website.
ObjectDock can be used as a program launcher, or as a complete taskbar replacement. Its functionality can be enhanced with plugins to provide features such as weather forecasts or news.
The above icon set is called Ecqlipse 2, it contains the Firefox icon (third icon in the black section) but it seems like not all icons are taken from the same set. Anyhow, you might be able to find other icons by looking for monochrome or black and white icon sets...