Microsoft has just published a new free extension for Visual Studio 2010 that provides an improved Add Reference dialog, an improved tab bar, and much more.
The new Add Reference dialog comes with a long-awaited feature: it's now searchable!
The tab bar allows you to display the close button at the end of the bar and not on each tab. It can also sort tabs by project and alphabetically. Tab color can vary by project or according to regular expressions.
I'll let you discover about the other features by yourself (HTML Copy, Triple Click, Current Line Highlighting, etc.).
The name of the extension is Visual Studio Pro Power Tools. I believe it's main features will come out-of-the-box with the next version of Visual Studio.