This is being
reported on
Red Ferret as Google's experimental new interface. As they point out, it's not exactly paradigm-breaking, but it has cool new features. I especially like the built-in Wikipedia sidebar on the right, and I'm guessing the feedback section will help improve the search algorithms or something. Plus, you get web page links and images in the same search, on the same page, which is neat.
If you start using it now, and it becomes standard, then you can tell everyone you started using it while Google was still being all stealthy with it, and thus build up your early-adopter cred =P