FilmJunk.com has a cool list of "Star Trek Inventions In Use Today."
After years of ridicule for being a Star Trek fan, it's official: THE ENTIRE WORLD OWES ITS CURRENT EXISTENCE TO STAR TREK.
Automatic doors. Biometric tech. Giant plasma screens. PDAs and tablet PCs. Communicators.
Star Trek either popularized it or was able to foresee/invent it.