Food rules my life, so it's important to me that I get a little exercise in whenever possible. To that end, I've taken to picking up my groceries by bicycle, and these Ortlieb Back Roller Classic Bags have totally improved my food shopping experience. The easy-on, easy-off latching device is ingenious: lift the handle to take the bag off the rack, hook the bag on and let gravity latch the pannier back in place. Because they hang on the rear rack, I can use them to carry heavy items like milk and bottles of seltzer, and their rollable tops can be closed to keep my stuff completely dry, or open to carry taller items like flowers or baguettes without smooshing them.
Ortlieb Back Roller Classic Bag, $148.50 for two at Amazon.com