While it's probably the most obvious and most common choice, I have to go with the Joe D. Ever since I was a kid and first noticed that card in the full color section of the Sport Americana price guides during the early 80s, I've always thought it was one of the best looking cards in the hobby, just on pure aesthetics.
I'd also echo Tony's pick on the Doerr. I had that card in my saved ebay searches for years, but never picked one up. Love the pose and background on that one.
Let's throw an honorable mention to the Gehringer card. Classic art deco, nice follow-through pose by Charley, and some World Series bunting in the background.
