I think the future of SEO is unbelievably good SE alogorithms. Now that Bing has entered the market, I think things are really going to change. Internet Search isn't going away anytime soon, so I expect the competition between Microsoft and Google to heat up quite a bit.
Within 5-10 years, I expect the algo's employed by SEs to be almost as good as real human eyes. I also expect the SEs to employ human eyes to evaluate content on the top sites to ensure that no site can "sneak" in with underhanded tactics.
It's hard to say what will happen, but something tells me SEO will be a completely different animal than it is right now.