We have become so acclimatized to doing what would have been the stuff of science fiction just a few years ago that the next big thing is probably already on your phone. You just don't recognize it.
You have the world's libraries at your fingertips, you can translate any phrase from any language to any other language, take a photograph and send it halfway round the world, find your way around a strange city with an ease once only possible for a native, forecast the weather several days in advance, type a report and print it out, or send it halfway round the world at the same time as the earlier mentioned photograph, have a conversation with anyone, anywhere with full color video, listen to hundreds of hours of music, watch movies, buy music and movies and have them delivered, instantly, and a whole lot more.
I'd say what we already have is pretty damned big, except that its contained in a device that is only four inches long. I invite you to be impressed.