First off, the least you could do is reuse your bag one more time as a trashcan. And Roland Kaufmann's V Bin is a great solution to help you do that. Its flexible sides adjust to hold up whatever bags you've got, and keep them from collapsing into a disgusting bachelor pad heap under the sink. Or, if you're partial to those fancy metallic canister bins with the nifty foot-powered lid, Tim Knossalla and Radtke Bjoern have the perfect solution for you with this Wull wastebasket. It uses regular Aldi-style shopping bags, but a clever mechanism lets it pop open on command.
Of course, everyone gets more bags than they can ever use for trash, so they end up storing them. Who doesn't have a bag of bags hanging on the closet handle, or a cupboard full of the darn things? With that in mind, Inna Alesina offers the Truly Yours fillable furniture line. Each cushion module is filled with grocery bags, and strapped together to provide custom configurable furniture that gets as big as you need (We love it, although some color or fabric couldn't hurt).
Finally, why not re-use bags to make re-usable bags! Rebagit by Piotr Stolarski re-forms old shopping bags into a new versitile sheet which can then be used to make sturdy shopping and messenger bags. He even suggests using the material for other products like lamps.
::MACEF Awards at DesignBoom::[by DM]
V Bin by Roland Kaufmann
Wull wastebasket by Tim Knossalla and Radtke Bjoern.
Truly Yours fillable furniture by Inna Alesina
Rebagit by Piotr Stolarski