Upgraded to Firefox 3, and downgraded back in an hour. Why? Because the native look and feel of FireFox 3 was making me suffocate. It may have been working fast, may have been consuming less memory, but it did remind me of the good old Konqueror as a web browser, which I never liked. FF3's font rendering on Linux platform is simply unimaginably awful.

Some of the times, upgrading to the latest version of a tool isn't exactly the right thing to do.