Juergen Schmidhuber is another notable AI researcher. He did an AMA a few days ago. He does believe in the singularity and that AIs will probably be indifferent to us if not hostile.
I also think he is the most likely person to create it. A lot of his research is general AI-ish stuff and not just deep convnets.
http://fusion.net/story/54583/the-case-against-killer-robots-from-a-guy-actually-building-ai/
(An earlier version of this article was titled 'Andrew Ng disses UFAI concerns" which is the phrasing many of the commenters are responding to).