If we're talking about "at present," I'd have to say my beloved Banana Republic Sloan ankle pants, which I have in every color. Runners up, the fab dress I got in Canada and the cobalt satchel Gentleman Friend brought me from Italy last summer.
But really, for my style moniker of Business Bombshell, the winner and still champion is my beloved pink patent Kate Spade pumps with the rainbow striped heels. They were my first major post-YLF purchase, and cost far, far more than I had ever paid for a pair of shoes before. That was nearly five years ago and I have worn them nearly to death. Not so much any more because the round toes aren't quite current, but I still love them and still wear them from time to time. And they still make me happy every day when I see them in my closet!