1. The Fastest Browser so far. I'm not exaggerating at all. Lifehacker has done tests on RC1, and it has turned out to be the speediest browser:
3. Smart Bar The Firefox Address bar is offically one of the coolest address bars I've seen. Like most browsers it will look through your history, and as you begin to type it will give you a list of places you've recently visited. But the cool part is the more you use it, that smarter it becomes. If you type in 'Tw' when you are going to twitter.com, and twit.tv shows up first, you simply can press the down button a few times to get to the twitter.com entry. The next time you type 'Tw' it will bring up twitter.com before twit.tv.
Firefox 3 has certainly won me over, and now I can't wait for the offical version so developers update all of their addons.