The Metro UI supports mobile technology well and many users might prefer this for the desktop also.  In case the classic start menu is needed, below is an early workaround:  An option for the classic approach might be beneficial for corporate users in a future build

WINDOWS 8: Navigating the Start Menu

QUOTE: If you have stumbled across the beta version of Windows 8 you may too be struggling with the new start button, it just takes you from the Metro UI to the Desktop and back. With the Windows 8 client that I am using as the developer preview, the behavior of the start menu is not ideal. The Metro UI is designed for touch screens and all programs are placed on the Metro UI, we loose any sort of ordering that we have with the normal Start Menu > All Programs. In addition access to the search dialogue that is so useful in Windows 7 is lost. Thankfully help is at hand with a simple registry key change, setting RPEnabled to 0.