Today’s a big day for Firefox enthusiasts: Mozilla announced the first public beta of Firefox 4, which includes a new, revamped UI, faster rendering engine, enhanced security, and some features that already exist in some of the competition like Chrome and Opera – things like crash protection for individual tabs and plug-ins (so, for example, Flash can crash without bringing down your entire browser, or one tab can die without bringing all of the rest down with it), and support for HTML5.

Of course, all of those things aside, most people will first notice the new interface, which brings tabs to the top of the window a-la Chrome, adds a “Firefox” menu that replaces the actual menu bar, and overall just looks like it fits with Windows Vista and Windows 7 (although it looks horrible in Windows XP – the massive titlebar ruins the look.) The new interface and new features may make Firefox competitive again in a world where Chrome, Safari, and Opera have been all gaining ground against it.

[ AppScout: Firefox 4 Beta Released ]