My "White Whale" would have to be any one of these three items:
* Ticket to Bobo Holloman's no-hitter on 5/6/53 @ STL Browns
* Scored program to Johnny Vander Meer's 1st no-hitter on 6/11/38 @ CINCI
* Vintage signed snapshot of James "Hippo" Vaughan
Sorry, one item only is a tough choice.