Laziness, not necessity, is the mother of invention. I predict that we'll turn out exactly like the humans in WALL-E pretty soon.
Seriousness begins.
I think stem cell research should be researched before moving to nanotechnology. What if someone whose name happens to be Liquid takes control of everyone's nanobots and kills them?
Screw controversiality in this line of research; if the United States can have an offshore base to torture people legally, then we can do the same with stem cell research. I bet more people are against torture than stem cell research; if not, something is seriously wrong. Besides, we can get true stem cell medicines up within the next decade, while it'll take a while to replace out internal organs with machines. It wouldn't work, as well; it would have to be done on every newborn; if it's going to take that much effort for maybe another year of life, then why do it? There are more important things to focus on, that are happening now, not in 2030. Global warming, rebuilding the economy, etc.