We collect Pencils, Pressed Pennies, Disney Pins and shot Glasses which don't take up much room in our luggage, but DD collects Disney soft toys and they do cause a bit of a problem!!!
I collect grey Eeyores, antenna balls, mugs and pins that really appeal to me. I also have a few favorite things that aren't exactly collections...books, crystal pieces, t-shirts, and some Radko ornaments.