Check out mozilla 1.5 which is ment to be the last version of the old mozilla suite, i think after this release spells the end of the intergrated browser. http://www.mozilla.org/releases/#1.5 [download] and http://www.mozilla.org/releases/mozilla1.5/ [release notes]
The stand alone browser, Firebird, now also has some additional features, namely web-panels and auto-download (http://www.mozilla.org/products/firebird/)
See http://www.mozillazine.org/ for more information.
Edit: PS: actually.. it seems that there will be a mozilla 1.6 see http://www.mozilla.org/roadmap.html
UserAgent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030930



1.5 under Linux is working fine so far.

