Given the number of active participants on LuLa (about a dozen, give or take), it is a miracle that the thread has reached four pages. Blame it on the premise: one best shot. A single best shot is best reserved for dead photographers and curators.
Epson ran an advertising campaign, asking famous photographers to hold in front of them a print of their most famous shot (e.g., Steve McCurry's Afghan girl). That is easier, and more suitable for still breathing photographers, but not necessarily for LuLa.
It seems to me that the approach Josh has offered has better chances: a story (article) developed around a single significant shot.