For me, it is Ruth, Ruth and Ruth. I'd add an Exhibit Ruth(s) that I don't have. It's pretty hard to go wrong over the long haul with Babe Ruth. I mean, he's Babe Ruth.
Second choice would be Jackie Robinson, probably either a 1949 Bowman or a 1952 Topps, or both if I could swing it. I'd probably lean towards upgrading my 52; it's a bit ratty.
But still one of my favorite cards.
Again, it's pretty hard to go wrong with Jackie Robinson.
Most players pass through baseball history, but Ruth and Robinson
are baseball history.