There has been multiple posts on then net in the last few days about how to get your start button back when using the latest Windows 8 Consumer preview from Microsoft (release last week). I have to say that initially I wanted it back also but I’m getting very use to not having it. This morning, I accidentally found an option that gives me a lot of what I was missing from the start button. Specifically, a listing of all my installed apps without having to either search through the metro interface to find them (by lots of scrolling) or knowing what it is called and just typing it once the metro interface is running.
All you have to do is first, bring the metro interface up by either moving your mouse to the lower left corner of the screen, pressing the windows button, or pressing the tablet button bottom center. Then, type a single letter indicating you want to search for something, then press the backspace key. you get the screen below with a nicely organized list of apps.
Hope this helps!