while browsing, IE 9.0 is the right one for you.
I am running on the RC release for some time now and would not want to miss it anymore.
Today I am installing the final release just downloaded from : http://windows.microsoft.com/de-DE/internet-explorer/downloads/ie-9/worldwide-languages
But, the new browser is not only interesting from an end user perspective. If you are a developer, you certainly are going to like the new built-in developer tools as well as the HTML 5 support.
My recommendation: Check it out!