If something looks a little different on Google.com, don't adjust your screen. Something is different.
The search box is bigger. The buttons below the search box are bigger and the text size for the query suggestions is larger as well.
Google suggested the reasoning behind the change was to emphasize their focus on search. That seems a bit strange to me, but whatever. If I had to guess, it would have been that search terms are getting longer and that senior citizens are one of the fastest growing demographics on the web. Plus, with tens of millions of Americans set to enter senior citizen-hood in the next decade, it makes sense to cater to that demo.
If you haven't noticed this yet, don't worry, you will.
On my computer, I was able to see the new, bigger box on Internet Explorer, and Firefox but not Chrome.
Check out the screenshots below. First is the new Google and below is the old: