I'm looking for some recommendations for storage bins. Right now I have a hodge podge of bins, some of the rubbermaid type, some of the more classic ones like this, and some of fabric bins. Believe it or not, some of our toys are in scholastic cardboard boxes! While I'd love to have everything in baskets, I fear that they won't hold up to being used all the time by 4 year-olds. What do you guys use? What do you like about your bins? What don't you like? Our director is hopefully going to buy the teachers uniform matching bins, and I want to be able to say, 'have you looked at this type?'