Microsoft will bring back the Start Menu with an update coming later this year. The size of this revised Start Menu is same as of the Windows 7 menu, but features miniature Live Tiles at the right side as shown in the screenshot.
In addition to the traditional Start menu, Microsoft has also revealed a new interface mode that allows you to run modern UI Windows 8 Apps in the normal desktop mode within its own window. Also, the upcoming update will improve the use for keyboard and mouse on Windows 8. (source)
