I’m using the release version of IE9. Works very well. Much faster than IE8, and I like the new features after getting used to them.
I use Symantec Endpoint Protection (corporate version), ZoneAlarm free, and Spybot Search & Destroy for malware protection.
And I have used AdMuncher since it first came out to block almost all internet ads and popups. Worth every penny. One of the best shareware products I know. I never see any ads (shhhh!).