For example: sites using Extended Validation (EV) SSL certificates will be very noticeable to end users from the Navigation Toolbar.
There's also antivirus integration for executable file downloads and malware protection. Malware protection warns users when they attempt to visit bad sites known to be hosting malware. The anti-phishing site features have also been enhanced.
On the other side of the battlefield is Microsoft's beta of Internet Explorer 8. They are working on similar security features.
Then of course there's Opera, which some of us in the lab use. Opera 9.5 is now available and it too has new security options.
All of this is good news for end users. Many of the malware samples and scams that we currently come across are targeting browser applications. So enhancing browser security and an increase in competitiveness is a good thing.
Update: Based on quick look of our usage statistics, a little over half of those that visit our dot.com site are using either IE6 or IE7. Firefox accounts for 20 percent, Opera 2%, and Nokia/Symbian 1%.