I'm big on the 8 of Wands, strangely enough. This fixation came about because of the magnificent 8 of Wands in the Victorian Romantic (not enough to make me keep the deck, but I'll never forget the epiphany that card gave me) and if a deck has a cool 8-Wands (not the usual abstractish wands-in-the-air thing) I'll prick up my ears.
I also look for the Queen of Swords (again, VR) and Death. That was the "make" card for me regarding the Universal Fantasy. I love that Death card.
There are three cards that I just don't get - The Wheel of Fortune, Justice and Judgement. If a deck treats any one of those cards in a way that brings it home to me, then it's a winner right there.
\m/ Kat