Anniversaries are always important and the forty-year milestone especially is. The couple may enjoy a gift that reflects their youth such as a record player, maybe with some albums to go with it. They might also appreciate more modern technology such as a Nook or Kindle. If you are looking for something a little more personal a family portrait is a nice way to get everyone together. If you enjoy sewing you could make a patchwork quilt. You could even have each child and grandchild submit a couple of squares or something they have embroidered and piece the whole thing together.