Who'd make a great US Post ambassador?

When I went to the post office yesterday with my mom to get some stamps for her christmas mail, I found out that the 80ct stamp had gone up to 84. I forgot what kind they were but it got me thinking. Usually, the 'everyday' domestic mail stamps (which are now 39cts, just watch them go up after New Year's) come in a pretty nice variety; we got the holiday stamps; Southern Florida Wetlands; Purple Heart reissue; D C Comics Super Heroes; Wonders of America; Hattie McDaniel just to name a few.
Well, consider the postage stamps we get from other countries. Mine usually come from the Netherlands or another European country or Australia or Canada and their stamps are quite nice and interesting looking. I thought that since the US has a bit of a 'PR' problem what not with an illegal and never ending war, a hard headed president and his ilk, a few international illegal actions here and there (hmm, say like torture), I think we need to put a new 'face' on the 84stamp that says, well hello..you got mail! But then in a friendly and inviting manner. What American depiction or association would you want see on that stamp?
I'm opening the floor with my first suggestion; Oprah! She's seen on television sets all over the world literally (109 countries). Tell me, what other suggestions would you have?