Mine is probably 7♠4♠. It's not a hand I'm actively looking to play, but it has won me some surprisingly big pots. I think part of the reason is that opponents rarely put you on a hand like that when you make a disguised straight or two pair. Of course, the reality is that it's still a weak starting hand and the math doesn't magically change. But every regular seems to have one "garbage" hand that has a much better personal history than it deserves, and for me it's 7♠4♠.