I am rather a fan of Arthur C Clarke's observation that "any sufficiently advanced technology is indistinguishable from magic" and the corollary (I just spent three minutes trying to remember how to pronounce and/or spell that word. It messed with my head) that until the technology is developed you may not know what's possible. This leads easily to the realisation that until you know about it, you don't know that you need it (fill in your own comments about mobile phones with cameras, hard drive PVRs, etc.). This is what separates the drivers of technological change from the people who are willing to put up with the status quo. Oh, and the ability to act upon the realisation they just had, of course. Watch New Inventors sometime.
My brother has a fantastic quote from Henry Ford in his email signature: "If I had asked people what they wanted, they would have said faster horses." I'm sure that Ford and Thomas Edison were of a like mind: "There's a better way. Find it."
All of which highlights the important point that those who argue that public funds should only go towards research that is directly, obviously of immediate benefit to the public (I knew someone like that. I had too much respect for him to argue too hard, and too little expectation that he would be prepared to change his mind) are blind to the fact that sometimes we don't know what research will benefit the public. The developers of Prozac, for example, have been quoted as saying that they weren't trying to cure depression, they were just mucking about with chemicals (I paraphrase, of course). The developers of Unix were doing much the same thing, as I understand it. Although there are those who would argue that this was not a good development...
In a similar vein, I have just spotted this report on Engadget: A robot that can swim through your bloodstream (Isaac Asimov's Fantastic Voyage, anyone?)
What really struck me, and what prompted the above musings, was this sentence: "Right now the doctors don't know what the medical applications might be, though they speculate that a large number of the bots could be used to fight certain types of cancer".
I love it. Right now they have no idea what it will be used for, but it's pretty cool, huh? Never let an absence of practical ideas stop you playing around with cool toys. I expect the bot to be used to de-plaque arteries and install stents, for starters.