About 4 months ago I came up with this theory that Apple will push it's users away from a full OS like OS X and take them more to something like iOS. I would never have agreed with something like that a year ago, but then I got an iPad and it made a whole lot of sense to me. Here's why:
I can do 90% of what I do on my PC on my iPad. The only things I can't do on my iPad that I do on my desktop machine is play specific games. Web/Social/Music/Video, heck I even edit photos on my iPad from time to time, because it's powerful enough to do that, and do it well. Obviously it's not as powerful as Desktop Photoshop, but it's pretty good.
But this is where it's interesting: iOS is INFINITELY less complicated than a desktop OS. There's no filing system, no complicated menus, nothing like that, but I can still get everything done. So why the heck do I need all the bulk and complicated crap in a conventional OS? I don't. Now, I'm a power user, much like 99% of us here on the forum, so an OS doesn't feel complicated to me at all, but man, I look at my parents and they still struggle to get their heads around XP. My mom got an iPad a few months ago and she's got no problems doing everything she needs to do on that thing. The fact that my mom can pick up a device and just use it without struggle says quite a lot about the OS.
So now, with the introduction of the App Store, and with Launchpad, you can see that Apple is slowly moving their OS into something that's less complicated than what it is now. I don't think that they'll eventually have iOS on their machines, but they'll most CERTAINLY be running something similar.
Mark my words - when we're old men and have 16 year old kids, our kids won't believe we used OSes as complicated as the ones we use now. Everything will be dead simple - no complicated file systems, no complicated control panels, none of that garbage.
That guy that used to mod cases. Now I take photos. True story.