I think Ray Kurzweil is a little...optimistic, if optimistic is the right word. "Crazy", maybe. It could very well be because I'm not nearly as immersed in the world of rapid technological change as he is, but a lot of his ideas just don't seem realistic. For example, he says, "Computers will disappear. Displays will be written directly onto our retinas by devices in our eyeglasses and contact lenses"...by 2009. Not even two years from now? I don't know if it's that I think we won't have the technology to do something like that by then, or that I think the computer industry has a large enough stake in preventing computers' disappearance, but I think computers are here to stay, at least for another decade or so. Maybe eyeglass devices will be in addition to computers. Really, who knows? I wasn't paying attention when the wireless headsets came out -- the really tiny Bluetooth ones -- but those probably seemed pretty out-of-this-world when they were first imagined.
As far as Bill Joy's theory that humans will make machines that are smarter than humans, and that will therefore be able to improve themselves to the point where humans will no longer be necessary, I think that is giving machines too much credit. Yes, machines can be "taught" to "think" and accomplish tasks by themselves, like Stanley the robot car, but everything Stanley did was a result of programming. He could not do things his creators had not programmed him to do; he could not think independently and come up with new ideas or better ways to do things. I think a key component of humanity is the ability, as a species, to think independently; not that every member of the species must be able to do so (I still think brain-dead people are human, even though they cannot think for themselves), but as a general rule, I believe this holds true (also with animals).
To sum up, I think both Kurzweil and Joy think too highly of machines.
I am very hopeful about the world I will live in for the next thirty years. Yes, we do have some fantastically complex and difficult issues that will need to be fixed, or at least dealt with: terrorism, war, nuclear threats, human rights abuses, pollution, apathy; but assuming we (as a human race) don't blow ourselves up or otherwise kill ourselves with weapons of mass destruction, I think we have a great opportunity to do good and improve people's lives for the better. If we do die off as a species, I am certain it will be because of something (or things) we bring on ourselves, not havoc wreaked by rogue machines we are smarter than we are.
I think the technological revolution in which we are living today is similar to past technological revolutions, just to a more extreme, rapidly-advancing degree. I do find myself longing for the days when people actually wrote letters, and often wish I didn't have to carry a cellphone around all the time -- it would be nice to really get away from everything for awhile, without everyone panicking because I didn't answer my cellphone for a whole hour -- and I'm only 23! What prevents me from believing in doomsday scenarios such as those advanced by Kurzweil and Joy (admittedly, Kurzweil doesn't think his is a doomsday scenario, but I consider it so) is the simple recognition of the fact that throughout history, people have feared technological advances, yet we as a human race are still thriving. It is somewhat similar to the fears over immigration: people are so convinced that illegal Mexican immigrants are going to be the death of this country and constitute an awful flood of humanity that must be stopped at all costs, but the Irish and Russian were also once considered a similarly foreign, unassimilable group, and they have integrated perfectly well into this melting pot we call America. I don't think things are ever as scary as the hysterical, fear-mongering-to-bring-in-higher-ratings media would have us believe. Cynical? I prefer to think of myself as possessing an untarnishable optimism about the state of humanity.
I am fascinated to see what the coming years bring, both in technology and otherwise, and just hope I will be able to keep up with all the latest advances!