Doesn't have to be valuable, just one you happen to enjoy.
1951 Ringside salesman sample: Objectively, this card has a lot going for it. It is a Marciano RC, it is rare, and it has multiple HOFers on it. Subjectively, I love the colors and graphics, especially the back. I think it is one of the nicest graphics packages Topps ever did and probably my favorite salesman sample of theirs.