Quick Look at Firefox 4 Beta - New Features With Screenshots
Firefox 4 is knocking at the door and the latest beta release looks just awesome. The seventh beta release introduces several important changes, including a revamped user interface (with the tab location above the address bar and navigation buttons), tab grouping, improved bookmarking system, re-open recently closed windows, built-in synchronizing system, rendering engine improvements, and more. This article contains a screenshot gallery with all the main features and changes brought until now by Firefox 4.
Here are the new features (with screenshots) introduced since Firefox 3.5: