The Mozilla Project has posted the first release candidate of Firefox 3.0 for Mac, Linux, and Windows. Firefox 3 is based on the much improved Gecko 1.9 Web rendering platform. Mostly this release focuses on small user interface improvements, tightened security, and improved performance and under-the-hood architecture, rather than big new features. Still. there are a few new features including:
I haven't tried Firefox 3 yet myself, but initial reviews are very positive.