Among Adobe's typefaces, Arno Pro, Minion Pro, Garamond Premier Pro and Hypatia Sans all support classical Greek. Be sure to get the latest versions (2007 or later) if you're looking at Minion Pro or Garamond Premier Pro for classical Greek.
But as mentioned above, Palatino Linotype is embeddable, so it should be okay if it supports classical Greek.
Cheers,
T