Baseball (and really any sports) jerseys are so damn expensive that I can't imagine buying one for a current player unless he's a slam dunk legend. I ended up just getting a Santo when I finally did get one because I wanted to make sure it would always be relevant. I don't think that really matters too much unless it's something really dumb like getting a Theriot or Barney or even Fukudome jersey. It's completely subjective, but those are the ones that stick out to me; if I see someone with a Soriano jersey, or Prior's, or Castro's in a few years it's just like, "oh, that's that player that was actually really awesome for the Cubs."