What is the most amazing technological or science concept you ever saw in sci-fi?

I always thought the SQUID device from the movie Strange Days was a cool concept. For those unfamiliar with the film, the SQUID device is a piece of tech that can record and playback experiences to/from media (I think it was a minidisc in the movie). It not only recorded the visual and audio, but the emotions, sensations, everything...

I would also recommend seeing the film to those that haven’t. It was a really good movie, that unfortunately didn’t do so well at the box office. Great soundtrack to boot.