There are things that look useful and then there are things that actually are useful.
Here's some that I think fit into the latter.
Addicted to Decorating suggested making a key ring to take with you with the colors from your decor. Then when you are out you won't have the problem I recently had- clashing whites, it was awful. :)
I have a few of these and they get used SO much!!! One holds exactly what is shown, another hols mugs, another sandwich bags. They make ones that you can drill into the cabinet too. The pic is from Amazon but usually just get mine at a store near me.
I hate all those skirt hangers. I'll be taking care of the kids or looking for a snack and forget I have one of those hangers in there with the groceries and in my cart it goes. I throw them away like they are infectious! Not any more! I'm going to turn them into chip clips like Money Saving Mom!
This magnet storage is from Martha but I've seen the same idea used for organizing cans in the garage or craft room, knife storage under cabinetry, for metal spice containers, and for keeping cook ware close to the stove but off of the counter.
The Shady Tree Diary came up with a list of uses for the soap boxes you can get in the travel size isle. Card storage is one of my favorites! Most of my cards are tied together with rubber bands! Other things she suggest is using them to store crayons and small art supplies. I bet the'd be perfect for small snacks, chalk, and hair clips too! I bet you could make a pretty decent portable make-up or first-aid kit out of one of these little guys! OK, getting to excited about his one :)