compare smart phones (i.e samsung galaxy 1vs3 or Iphone 1,2,3,4)
or televisions (tube, plasma, LED, LED)
or portable music (transistor radio, boombox, walkman cassette player, walkman cd, MP3 players, etc.)
telephones in general (original, corded, cordless, cellular,etc.)
You could start by telling stories from the past (i.e. losing a friend at Disneyland and searching for them for hours because there were no cell phones, etc.)
Discuss the advantages and disadvanatges of both the old and new technology (i.e boom boxes had better sound, but MP3 players are more portable and hold more music)..