In fact, I would address the letter to J.W. Marriott, Jr. himself (with the cc to the Philadelphia property General Manager). E-mail is fine if you wish, but for this kind of mater, I think that written correspondence is more appropriate and has a better chance of being seen by someone higher up in the management chain (it's my understanding that letters sent to Mr. Marriott's personal attention, although probably opened and read by one of his executive assistants, *will* be read and responded to).

The address is:

J.W. Marriott, Jr.
Marriott International
10400 Fernwood Road
Bethesda, MD 20817


You can optionally add something like "PERSONAL ATTENTION OF ADDRESSEE"

Last thing: Keep the Priceline angle out of it - you're addressing Marriott corporate management on an incident where your travel plans were disrupted by the actions of MARRIOTT employees, so keep the focus there.

Best of luck and keep us informed on further developments.