Google changed its interface? The new look is only on the google.com site for now. The .ca, .fr, .co.uk, etc. are the usual blue bands. Update: The new interface is due to their combining of various search types they had e.g. web, images, news, etc. They are also supporting a toolbar at the top for various services.
Its so polished that it looks too shiny to me. The shiny bar gives a very Web2.0 feel than the earlier more pleasing colours. Blue band felt plain and simple.