Safari for Windows launched today/yesterday, and while I have worked hard as a mozangelist, I think this is a good thing. Safari comes with third party extensions (webkit) which I have not played with, but after becoming addicted to XUL in FireFox, which I believe is wasted as a UI layout and script engine, I would love to see what Webkit can do.
It’s very easy to write your own browser app, or extension, in XUL and a bit of javascript. XUL has cult-like following, and Quirk has built an amazing extension with it. Would love to see other social bookmarking (social spying) apps come out of Safari.