For me, it would have to be;
1) The first photo ever taken of Lou Gehrig in a Yankees uniform. From the Bill Mastro Collection.
GehrigYEE2010.jpg1923GehrigJoinsYankesNEWSPAPERcloseUP.jpg
2) Pittsburgh Pirates Roberto Clemente Memorial "21" Patch that was worn by the 1973 team. Also from the Mastro Collection.
Clemente21Patch.jpg
3) This was a tough decision, but I'm going with this 1958 TYPE 1 photo of Mickey Mantle & Henry Aaron crossing their bats at the '58 Series.
mantleANDaaron.jpg
what's yours?