I originally posted this in the "Windows 8 RTM allegedly leaked already" news item comments, since that really sparked the availability of the final version of Windows 8. I know lots of folks want to skip the Start Screen, and it can be done.
With that said, since Windows 8 is now here (unofficially, at least), it might be a good time to throw a plug out to the good guys at: http://classicshell.sourceforge.net
For those not familiar with it, it was originally created to bring back the hierarchical Start menu -- long before Windows 8.
The full screen replacement of the Start Menu has no doubt been one of the more controversial aspects of Windows 8. ClassicShell's implementation of the Start Menu is really clean and not hacky at all. By default, it captures the keyboard's Start key and opens the menu (You can choose the XP's Classic style, Luna, Vista's, or even their own custom Metro skin) while leaving Shift-Start to be used to call the Start Screen. And even better, they implemented a search box so you don't lose that capability either.
There's an option as well to boot automatically into the desktop. You'll still see the start screen upon boot, but it really just becomes a splash screen at that point. Since the Start key's behavior is captured to the menu as well as the bottom left's Start Screen activation disabled, you don't ever have to see the Start Screen if you don't want to.
Thought I'd share!