First, as the others have said, consider your own needs and desires. Then, consider your own needs and desires. The future of computer technology means nothing - unless you specifically want to be on that cutting edge. If you do, that's fine. Just buy the latest cutting edge machines with the latest cutting edge software.
But if you aren't specifically looking for that, then consider what you want to do with your computers. How do you use them? Pick the machine(s) and OS(s) that work for you. I don't like the direction computers are going in, at least the commercial systems. So my next computer will be one I build, and I'll put my old copy of Windows XP on there (just to run a few things I haven't managed to wean myself from yet), and whichever Linux distro best suits me at the time.
If you want to go out and buy a Windows 8 box the minute it comes out, I support your right to do that. But if that isn't what you're looking for, why let someone else tell you it is what you ought to have? So, yes, I'd spend some time thinking, and I'd work out what I wanted to do, and how, and why, and then I'd choose the machines that suit me best. (I know some people don't know enough about computers, and they're happy just letting a salesperson point them towards something. That's their right, too, and it's their money. But I've never been happy with anything a salesperson picked out for me. In my experience, it seems like stuff they must have been trying to dump. That's one reason I learned more about computers. In self defense.)
Edited to add: At least for me, the problem with salespeople isn't just with computers. I am never happy with anything they pick out. I love fountain pens, but the few times I let salespeople tell me what make and model to get - I got stuck with crap. My cheap Chinese knockoff pens are better than those.
I have specific tastes, and the only way I can get what I want is to figure it out for myself.
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AQ Test = 44 Aspie Quiz = 169 Aspie 33 NT EQ / SQ-R = Extreme Systematising
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Not all those who wander are lost.
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In the country of the blind, the one eyed man - would be diagnosed with a psychological disorder