TFS Power Tools was just updated and released on August 18th. The new version includes a feature I've really been missing: Work Item SEARCH. How could this have been missing for so long? Well now it's in the TFPT.
It's a little hidden. You have to use the Work Item Tracking toolbar to do the search. So if you've hidden most of your toolbars like me, then you'll need to show it again to see the search.
Here's a good overview from Brian Harry's blog about what's included. You can grab the extensions from the gallery.