There is a very interesting discussion in mozilla.dev.apps.firefox newsgroup about some changes proposal for the Firefox 2.0 interface. Mike Beltzner discussed his proposal around an ASCII mockup with many points which will make Firefox 2.0 will look really different but have better usability and great improvements for browsing web.
http://firefox.phpmagazine.net/upload/2006/03/firefox2-thumb.png

The default chrome of Firefox has not been altered since the launch of Firefox 1.0. It would be presumptuous to assume that the way in which users interact with their browsers has gone unchanged between that time and our planned 3Q2006 release date for Fx2, and even more presumptuous for us to assume that we got things 100% right with Firefox 1.0. Ben’s been thinking about this for a while, and he and Joe and I got together today to take a good hard look at the browser window with the following goals:
– remove UI elements that aren’t useful to majority of users
– increase usability of elements that are useful
– increase focus on web content