Start8 can help you bypass the Windows 8 start screen and go directly to your desktop.
Update, October 18, 2012: Early versions of Start8 required the user to choose a setting to enable automatic desktop. This post has been updated to reflect the changes to the latest version of Start8, which defaults to automatic desktop.
The start screen in Windows 8 has been a polarizing change from Windows 7, to put it mildly. If you click the desktop tile immediately after logging in, a free program by Stardock can save you some time. With Start8, you can automatically load the desktop immediately after logging in to Windows 8. Start8 will even add back the Windows Start button.
To use Start8 to bypass the Windows 8 start screen, go to Stardock's Web site and sign up with your e-mail address to get the download link. Previous versions of Start8 did not enable automatic desktop by default, but the latest version takes you straight to the desktop without any further action.
If for some reason you prefer not to go straight to the desktop, right-click on the Start button, then select Configure Start8. In the Control section, uncheck "Automatically go to the Desktop when I sign in."
That's it. Start8 has added many new features from just a few months ago and makes a great little supplemental program to Windows 8. Keep in mind that Start8 is free while still in beta, but will cost $4.99 when the final version is released.