Ruff Bowl
It's nearly universal: if you own a dog in an urban area, odds are you walk it using some sort of retractable leash, and need to scoop up its droppings after it's done doing its business. The Ruff Bowl ($8) is designed for exactly these situations. It clips easily onto most retractable leashes, holds used poop bags away from your hand, and can hold up to 4.5 oz. of water when it's time for Fido to take a drink.