My favourite card is the Thoth deck, Queen of disks. First time I saw it reminded me of my wife. Years later I finally learn tarot and discover she is indeed the Queen of disks.
I like cards that have oodles of personality. So quite a few from the zombies fit that criteria, but the queen of spades is my avatar and is the stand out fav
The World from the Mary-el. There isn't anything I don't love about this card- the colors and how they seem to separate the card in half, the look on her face, everything.
Oh, and a third that I got only recently: the Ten of Swords from Baba's Fairytale. Probably the most beautiful and poignant 10 of Swords I have ever seen.
Magician in RWS (What fantastic symbolism this card has...the infinite on his head, all the suits on his control. The wand pointing to the earth and to the sky...just beautiful) and in the Cosmic Tarot (http://kathryn.mnsi.net/1.jpg)