I have always been a fan of strong plastic bags that can be reused. Because of their ability and very green nature, the importance of being used over and over again, they are often given brilliant decorative graphics and colours.
Sainsbury created a brilliant bag presenting the union jack flag made from a photo of fresh strawberries collaged with blue pieces on a white background.
At one point I was working on this bag to create shapes and patterns of a random dripping nature using glitter glue, which when peeled off the plastic once dried would also peel away the coloured print underneath - leaving only the white plastic.
Remember to re-use your bags.