Delete your cookie for google.com. It drove me nuts too.
Well, this will give me an excuse to sample other search engines. I was a heavy Altavista user until I found this new search engine out of Stanford ..
While doing such large A/B tests, they should definitely give an option to opt-out. Or at least a prominent feedback button to tell them how bad is their new design. It is as if Google will A/B test a new design and no-one will notice it?