Firefox 4.0 is coming along nicely. Just check out the ideas that are being tested out. The download panel idea catched my eye as the most interesting one. Looks really cool plus it saves on a lot of screen real estate when you don't need it.
More and more, the Firefox developers are showing that they most certainly are not copying Chrome. Quite frankly, there's nothing wrong with following a good example. Google showed the way and just about everybody else followed.
Firefox though looks like it's trying its darnest to make it even better.