Love my little crossbody bag! I used to always carry a huge purse, so I'd put card/id/keys in my pockets for short trips to the grocery store or whatever, and then end up misplacing/forgetting my debit card in the laundry, so I had to find a solution. On a whim, I bought a cheap crossbody bag from Kohls, and I've been in love ever since. It carries everything I need, is hands free, and I never have to worry about it being snatched from my shopping cart or left somewhere, because it's always over my shoulder.
Daily I carry my face powder, phone, 8+ cards in the purse's sleeves, tampons/liners, cash, keys(I'm down to 4!), hairties, a few kleenex, pens, and the week's receipts, with plenty of room to spare for things I'll need only on certain days, like sunscreen or makeup. Most other things (baby wipes, headphones, deodorant, spray sunscreen, etc) I keep in my desk, in my car, in my gym bag, or at home. It's really amazing how much the little bag will hold though, and I love that it's so organized and I never have to dig around for something in the bottom of a huge bag. I've never once thought "I wish I had a bigger purse" since buying the little one.