I don't mean "my ability to love again" or any of that shite, I mean actual proper physical things that your previous lovers have nicked and never returned.
My ex-boyfriend (three years ago) stole my copy of Betrand Russell's "The Problems of Philosophy", and it still narks me off to this day.
Bonus question: what's the best thing you've ever been left with? I've still got a jumper. And somewhere, a No Doubt CD.