Future Tech, or, how much is too much?

Here’s one for the sci-fi geeks in attendance.

In a sci-fi story, especially one set in the near future (say, 10 to 20 years from now), how is the best way to handle the technology? With current tech running the way it is, becoming more and more ubiquitous in daily life, it’s impossible to just ignore technology in your story. Well, that is, unless there’s a Butlerian Jihad kind of event.

Researching the trends and extrapolating is great and all, but how do you know if you (or the author) took it too far? In my opinion, for example, 20 years is not enough time to develop, say, teleportation. Well, without alien intervention, anyway.

Have you seen places where tech was taken too far? Or not far enough?