Ooooh this is a tricky one! How can you select a favourite card from the 78 available? And then how can I pick one image from the hundreds of decks out there?!
Initially, I was going to say that it must be Death that is my favourite card, because when I'm buying a new deck, Death is one of the cards that I go straight to, to see how the artist has rendered it. If Death appeals to me, then the chances are all the other ones are looking good too!