Vincent Müller and Nick Bostrom have just released a paper surveying the results of a poll of experts about future progress in artificial intelligence. The authors have also put up a companion site where visitors can take the poll and see the raw data. I just checked the site and so far only one individual has submitted a response. This provides an opportunity for testing the views of LW members against those of experts. So if you are willing to complete the questionnaire, please do so before reading the paper. (I have abstained from providing a link to the pdf to create a trivial inconvenience for those who cannot resist temptaion. Once you take the poll, you can easily find the paper by conducting a Google search with the keywords: bostrom muller future progress artificial intelligence.)
I should note that it's not obvious what the experts responding to this survey thought "greatly surpass" meant. If "do everything humans do, but at x2 speed" qualifies, you might expect AI to "greatly surpass" human abilities in 2 years even on a fairly unexciting Robin Hansonish scenario of brain emulation + continued hardware improvement at roughly current rates.