Since June of this year, Google has been testing a top down user interface navigation. In fact, they even confirmed the test in September and a few weeks ago, I went on record saying this will be rolled out soon. Yay, I was right.
But I am not happy that I was right. Google said this is a "simpler, cleaner design on the search results page." Yea, for now. I suspect this white area will be used to plaster all sorts of things at the searcher.
In fact, this is what I posted I'd think it turn into back in September:
I am currently not too far off, here is what it looks like now:
Mark my word, it will get messy and annoying.
In fact, the forums are filled with complaint after complaint about the new interface. Now, that is always the case when Google makes a user interface change, so nothing new there. But I really think this is setting the groundwork for some major changes to how Google sees their search results page and is it for the better? That is up for the searcher to decide.
Forum discussion at Google Web Search Help and WebmasterWorld.