It is only a beta, but this is good news for those of us who always wonder what our pages look like on the Apple Safari browser: Apple Introduces Safari for Windows. It is a free download, and it does seem to render pages very quickly, even though it is still beta software. Safari has tabbed browsing, but I do not see any indication that it supports extensions.
Also just released in beta is version 9 of the Netscape browser, available at the Netscape download page. I think it is slicker and faster than version 8. It no longer allows users to toggle between the Firefox and the Internet Explorer engines, but that function is available with the IE Tab plug-in which works in Navigator as well as Firefox.