Great topic, mmfelesi, and great answers.
I can't top Ross's backside, but for fronts, my overall favorite is the Sola-Busca Ten of Cups. His face is that of someone who, despite everything, feels blessed. I imagine that the cups surrounding him are his loved ones, either his family or the simple townsfolk he has served so long. Since the colored version I have is not a photograph of the original, I give the black and white photo as well.

But he doesn't exactly reflect the tarot as a whole, something I would expect from a "Mr./Ms. Tarot." That honor seems to me to go to the Bateleur, with his symbols of the four suits and his theme of magic. The Noblet is probably my favorite, with his phallicism and his odd table across a stream, on which are odd objects suggestive of occult interpretations. His insecurity (given his sidelong glance) suggests that he is young and near the beginning of his quest. Flornoy didn't title his book "Pelerinage des Bateleurs" (Pilgrimage of the Bateleur) for nothing. There is also the PMB Bateleur, with his mystical look, his Eucharistic cloth, his wonderful hat, and just enough of the fourth table leg to tell where it is.

Among tarot females, my favorite is the Conver 1760 star-lady, for the pleasure I get trying to seduce her into revealing her secrets. Otherwise, the Noblet Queens all have a lot of personality, especially Swords for the look she gives her weapon. Her d'Este counterpart is another favorite of mine, for her wistful look as, I imagine, her condottiero husband rides off to war yet again.