It struck me that I don't always remember someone's books, but I always remember some architectural or interior design feature about where they live. My father does an amazing job putting faces to names, but even with people I've known for years, it's something about their house -- the fireplace in the living room at jaehop, the layout of the upper floor(s) at iconoplast's parents' house when we were in high school, the artwork in my grandparents' living room, the kitchen windows at the McCombs' house in Evergreen.
Even stranger, I can draw interior layouts of every place I've ever lived. I once drew the house we lived when I was 3 because I was sure there was an olive green vinyl screen that slid up against the wall that could be closed to separate the stairs from the room they ascended from. After I sketched the texture of the fabric and the latch/handle hardware, we dug through old photos and found proof. I'm a little creeped out by that, but maybe my memory for details like that will be a marketable skill someday.
So what do you always remember people by?