I've decided that my car needs a basket one that hops in with me in the morning and heads back inside when we're home. I can set it by the door so I can throw in anything that I will need for the day, returns, forms, snacks for the kids, etc. Not to mention while we're out I can put anything into the basket that I don't want to lose [or stuff in my handbag] to make sure it actually makes it out of the car.
Here are a few baskets that have my fancy. I can't decide big or one that flattens.
All baskets from The Container Store.