The backpack was once a school essential, but now the eminently practical carryall is a street style staple. Initially, when backpacks came on to the fashion scene a few years ago, I was opposed. Too cumbersome, I thought. And maybe even a little tourist-y looking? But now designers are making backpacks in luxe fabrics, and many of them double as hand bags, so you don't have to sling it on your back. On those Sandra Bullock in Gravity days (i.e. when I'm feeling like I'm up against perpetual adversity!), it would be nice to have a big (and stylish) bag of tricks, stocked with everything from emergency snacks to various hand-held devices to an extra layer to throw on in case I get cold. Prime examples include this calf-hair Elizabeth and James, this white croc Topshop, and this slick, zipper-accented Phillip Lim.