Old milk crates are awesome and also have the added value of being both decorative and functional. I have one in my collection that I use for DVD storage and beagle protection.
I haven't come across any of the wooden ones in ages. Generally I don't buy things that take up too much space, but I do bring home the plastic ones when I see people throwing them out since they're useful for storage.
Thanks everyone for all the views and reply on this thread! Wasn't watching this one so I never saw the replies until today. Amazing collections everyone!