Profile Visual Studio

Open Commandwindow in %AppData%\Roaming\Microsoft\VisualStudio\10.0
Run git clone https://github.com/lcorneliussen/ActivityLogProfiler
Start Visual Studio with /Log switch
Run deploy.cmd (will overwrite default ActivityLog.xsl in parent folder; Visual Studio will replace it after restart!)
Open ActivityLog.xml in Internet Explorer

Read more on my blog: http://startbigthinksmall.wordpress.com/2011/11/08/activity-log-profiler-find-out-which-extension-is-slowing-down-your-visual-studio/