Check it out (http://arstechnica.com/news.ars/post/20060710-7229.html) and as always, download are your own peril.
A lot of interesting new features including:
-Anti-phishing tool
-An integrated spelling checker for web-based text input forms
-Automatic extension verifier
-New tab features
Most of the work seems to be under the hood that addresses some of the bugs people have had (memory leaks, weird cache behavior, etc).
Features that where once plugins keep sneaking into the main program. However I don't mind as most of the features are ones I already consider essential.
Ilove this though...its a release candidate for a beta. Truely remarkable. This also shouldnt even be a 2.0 release the biggest part of this release isnt even gonna make (enhanced bookmark management). This should really be like...1.75 or something :P 1.9 even