On the guest book table we displayed photos of our grandparents from all of their wedding days. Only Brandon's paternal grandmother is still living and wasn't able to travel to the wedding, so it was nice to at least have pictures of them all there. We decorated the table with fresh magnolias, hydrangeas and roses we cut that morning, and put them in a little antique teapot and crystal perfume bottles.
For your wedding reception memorial table... matching frames (of varying sizes) + memorium candle + mirror disc... sprinkle in the tealights and flowers/petals. Keep it clean and classy and in-theme with your wedding.