There's also better HTML5 support, WebGL for 3D awesomeness, and Firefox 4 beta 7 can now utilize OpenType fonts on Web pages. You're looking at the final version of Firefox 4, really. Since no new features will be added from this point forward, it's all about squashing bugs and preventing crashes between now and launch day.
We'll have more Firefox 4 coverage throughout the day, so stay tuned!
Download Firefox 4 beta 7