"Man is a marvelous curiosity ... he thinks he is the Creator's pet ... he even believes the Creator loves him; has a passion for him; sits up nights to admire him; yes and watch over him and keep him out of trouble. He prays to him and thinks He listens. Isn't it a quaint idea." Mark Twain
I decided on the laser, because it is used in so many things and is really useful. Plus, if not for the laser, many evil death machines used by villains in the attempt to kill superheros would not exist.
The other inventions that I considered for best were modem, solar cell, hovercraft, internal pacemaker, black box, and microchip.
"Man is a marvelous curiosity ... he thinks he is the Creator's pet ... he even believes the Creator loves him; has a passion for him; sits up nights to admire him; yes and watch over him and keep him out of trouble. He prays to him and thinks He listens. Isn't it a quaint idea." Mark Twain