Cupertino, start your photocopiers
It looks like Safari 4 copies Chrome’s UI wholesale. Besides Safari’s separate “Address” and “Search” boxes, everything — including Top Sites — is the same. On Windows, the similarity is even more striking. For example, compare this image to this one. Notice that, in addition to the titlebar tabs’ position and the top sites grid, Apple has also copied the “page” and “gear” menus to the left of the location field.