If you’re attached to the search box in the Windows 7 Start Menu, a quick registry edit will return it but the unfortunate side effect is that Explorer and Task Manager will also go back to Windows 7 mode.
Switch Your Windows 8 Start Menu Back To Windows 7 Style

I dislike the searchbox immensely, its way too slow to be practical in my experience.
The keystroke behavior in win8 is still the same – press the Windows key, then start typing. The difference is that it shows up in the metro interface