If you have not installed the latest version of the Visual Studio Productivity Power Tools (The LATEST release that is), you are missing out on some killer functionality.

Download them here:
http://visualstudiogallery.msdn.microsoft.com/en-us/d0d33361-18e2-46c0-8ff2-4adea1e34fef

There is now a Solution Navigator:

Advanced object information when hovering over an object or method with your cursor:

Cool new color coded gradient backed tabs:

Pinning of tabs is still supported:

Check out more info on the Visual Studio Blog
http://blogs.msdn.com/b/visualstudio/archive/2010/07/20/solution-navigator-blog-post.aspx

Download the latest version of the Productivity Power Tools
http://visualstudiogallery.msdn.microsoft.com/en-us/d0d33361-18e2-46c0-8ff2-4adea1e34fef