Who is Most Collectible?

As a Mark McGwire collector, I have found that there is a whole slew of fellow Big Mac collectors out in the sports card world. And, inherently, they are always driving the prices up on ebay. However, there isn't the competition for McGwire cards as there is for more popular players. So, Here is the question. Who is the most collectible player in all sports? 

Its a tough question, and we'll never get a true answer, but I think it will be fun to see what the SportSecurities readers have to say. Take a sec and give me your vote.