I read today on Sara Ford's blog a VS trick about forcing VS to put the MRU file opened on the far left.
As you open up files for viewing/editing, they're added to the tabs to the right of the current one. Well after opening a few, ok, more than a few, they start to drop off out of view! :< It can be frustrating cause chances are the files you're looking at only once in a while are already in your face on the left, but the ones you REALLY want are gone! Sara's got a fantastic registry trick to fix that! The trick forces all the most recently used (MRU) files to the far left, therefore the more recent the file is, the further to the left it is.
If you just want the reg key, here it is.
Under the HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\9.0 key, you can create a DWORD UseMRUDocOrdering = 1
If you want more details, please visit Sara's blog.