Ian Morris on "why the west rules", which seems to be a provocative title for an interesting book on historical geographical trends and their projection into the future: http://www.youtube.com/watch?v=tvkHiL-H2io. He starts talking about the future at minute 27 and basically concludes that a singularity scenario is one of two possibilities for the 21st century, the other being collapse. Nothing new, but encouraging to see this increasingly in the mainstream.
Restriction to 21st century is an important element of the question. If you state the same about the next 10 years, then clearly most likely neither extreme will attain.