Seat back storage

Hi everyone, in order to make use of the driver & passenger seat backs as storage space for our rear passengers on long trips, my wife and I decided to purchase these from Amazon.ca:

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They have velcro straps that fasten around the head rest posts, and we use black shoelaces to secure the bottoms. They have various mesh pockets for stuff and fold out water bottle holders, and they're black so they match the interior of our Micra. We were actually quite surprised by the sale price ($5 each!) and they were more substantial than we though they would be; we'll see how they wear after a while...

The two grey fold-down trays (behind the driver's and front passenger's head rest) we bought years ago at Regal (yes, Regal) and have used them on the old Suzuki Esteem wagon before transferring them to our Little Guy. :)

What are some of the options you've used, especially if you have kids in the back seat for long trips?