We had hundreds of documents that used a very old version of the Lithos font called LithosBol. The Intel iMac would not recognize the font and substituted Geneva. There is a new version of the font called Lithos Pro Bold.
On the Intel iMacs, I copied the new version into the top-level Library/Fonts folder, and renamed it to LithosBol (the name of the old version). Bingo -- the new version was accepted with the old name, and everything looks just fine. To date, the Intel iMac has not exploded.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20060220103253682