Vacuum Storage Bags
See the thing with these vacuum storage bags is that they not only save heaps of space, the very act of watching a massive stack of pillows turn into an airtight package that is flatter than a pancake, is immensely gratifying. Kind of like popping bubble-wrap. I just can't get enough of it.
Travellers will love them too, especially those who tend to over-pack or over-shop when on holidays. (Yes, that's me.) Just remember that you do need a hoover to suck the bag airtight again at the other end. Be prepared to get some weird looks at reception when you ask for one.