Every day my kids used to bring home artwork from school and it was hung with great fanfare on the fridge, the windows and the doors of our kitchen. New creations took the place of the old in our ever changing gallery and the valued masterpieces were placed in huge bins in the attic, never to be seen again.
Why not preserve some of their favorites by creating a book? You scan or take pictures of their favorites and organize them by school year.
If you would prefer to leave it to the experts, Plum Print.com will do all the work for you starting at about $85 for up to 30 pieces of art. They have a great web site with lots of ideas and galleries of books they've created. There is also a fabulous video of a TV segment about what to do with your kids' art, which includes everything from using it as wrapping paper and birthday cards to having pillows and stuffed animals created from your child's designs.