What's interesting is the amount of effort Apple has put it to emulate the OS X interface on Windows. It doesn't go anywhere near this extent on any other of it's high profile Windows apps (iTunes and Quicktime). I think they've mimicked the OS X Safari because they wanted the rendering to be identical between the two, although I've not yet tested this. This will make developing for Safari far easier for Windows users, as it'll render the same in Windows as in OS X, and then you'd logically assume it would render the same for iPhone's Safari - opening up iPhone app development to millions of Windows based web developers.