I found that you don't even have to hit enter to open up the Google search page to view the result. As soon as I finished typing GB, I got the result as an auto-suggestion. This also works for mathematical calculations.
I was using Firefox 3.0. I saw the auto suggestion list similarly with the result in Chrome's Omnibox as well but didn't see this happening with the Search bars in Opera 9.6 or Safari 3 (on Windows) or IE 8