I've recently been reading Nick Bostrom's book Superintelligence and must admit it stuck with me. It may well seem a tad abstract to us who are new to thinking about such matters, but highly stimulating and thought-provoking.

The main point is driven home thoroughly: We should be talking more about artificial intelligence! Because its arrival might be just around the corner and it has the potential to mark a crossroads for our future, the choices being really really bad or really really fantastically good.

If you havn't read them yet, these two blog posts by Wait But Why are probably the best introdution: Part 1, Part 2.

I am currently half-way through Olle Häggström's Here Be Dragons which covers related but broader toptics of near-future technologies.