I'm surprised no one has said the 2 of Swords. It has got to be one of the coolest-looking cards in the deck.
Actually, the 3 of swords is very powerful too, even if it's not very popular to get in a reading. The 8, 9, and 10 of swords are very evocative too.
My favorite Wand for some reason is the 3 of Wands. I associate with it but I'm not sure exactly why. Maybe it's the hair.
I love the 3 of cups (I love parties too), but also find the 5 and 7 of cups to be extremely compelling.
I love the 9 of Disks, and actually secretly like 4 of Disks. It's speaks. It almost looks like his throne is floating in air, and it reminds me of how money can make the seemingly impossible happen -- instead of seeing it as miserly, I see it as being related to the mysteries of worldly power. His arms look like the arms of a spiral galaxy emanating from the coin.
I love the look of the Magician, Death, the Moon and Star. The Moon has a creepy-scary element to it though. I really like Fulguor's altered Priestess. The High Priestess is actually one of my favorite cards, but the RWS version not my favorite version. Too Christian-y.
It's funny. Some cards I love the energy of, but don't like their RWS visual design. Like the Chariot. I've seen way better art.