It was flown at half staff for John Paul II
http://georgewbush-whitehouse.archives.gov/news/releases/2005/04/20050402-3.html
So we have Pope John Paul and maybe Churchill. I thought about Churchill as being an exception if I were deciding, but decided against that even though I have a tremendous respect for Churchill. Popes also came to mind, but then there is the religious angle and the 1a bashing that would probably occur.