The Quick Version
I have spent a lot of time in these pages explaining why Windows is a poor choice as a home computer (see Windows or Not?). If you have read all that and you're still absolutely convinced that your world will end if you don't have Windows at home right now and you have a note from your mum signed in triplicate stating that you understand the consequences and despite all that you are still going to go for it, then I promise to do my best to get you a good one.
Why get an All-in-One as opposed to any other shape of Windows machine? See What Shape? for all the details, the short answer is these machine are neat, tidy and good looking (at this point I wanted to say "like me", but my proof reader said that was not allowed).
WHICH ONES TO BUY?
If fate says you have to have Windows then we are going to make sure we get the best possible machine for you (just make sure you read Protecting Windows so as to give you half a chance of keeping it infection free). When asking me about Windows computers people seemed very keen to ask about brands, "is HP better than Dell or Lenovo?", that sort of thing. In truth all the major brands make good quality hardware that are all of a very similar standard. That doesn't stop geeks talking endlessly about which one is best, like petrol heads comparing cars, but for normal people the differences are small.
The way to choose a Windows All-in-One is on price and looks. Never pay extra for a touch screen (if the machine you choose happens to have it, fine, but never pay extra for it), because touch screens on All-in-Ones are a gimmick. Here's why: to use it you have to hold your arm out in front of you, your arm will quickly get tired doing this and you will then stop using the touch screen. This stuff is not a problem when using a touch screen on a tablet (because you hold it like a magazine), but a touch screen on an All-in-One is a party trick you use to show off to your friends.
Right now it looks like Lenovo have the best bargains on their model C560 (US $629 - UK £579). It's a nice fast machine with a big screen (always get a screen bigger than you think you need, people always say "this is too big" when they get a screen a size up from their last machine, then after a few days they can't imagine how they ever worked on the smaller one. Trust me, I have seen it so many times).
Personally I always remove the hard drives this sort of machine comes with (typically a 1Tb spinning drive) and replace it with a 128Gb or 256Gb solid state drive (SSD), because it goes so much faster with one of those. The manufacturers typically keep the SSDs for their top of the line kit to give you a reason to spend more. But if you fit an SSD in a normal machine it goes like the top of the line kit anyway. It's not the right upgrade for everyone, as some folks have huge media collections that won't fit on the smaller drives, but for most folks it's a very cheap way ($100 with fitting at your local computer workshop) and a very effective way to make that machine fly. In fact once you have used a computer with an SSD, it's hard to go back to a spinning drive, you just want to kick the thing out of your study if it makes you wait one more time.
HOW TO FIX WINDOWS 8
Unfortunately all these machines come with Windows 8.1, which has been about as popular as genital warts. To give you some idea Microsoft will be calling the next version Windows 10. What happened to Windows 9? It never existed and never will. The marketing people know that Windows 8 was so detested they wanted to distance themselves from it as much as possible. It kind of leaves you speechless doesn't it?
So what the hell am I doing recommending computers with Windows 8.1 on? Firstly I did say only buy Windows if you have to (Windows or Not?). Secondly I also said you probably don't need Windows even if you are convinced you do. Thirdly you can buy laptops with Windows 7 on, but it limits your choices. Fourthly, there is a fix. Grab a copy of StarDock's Start8 and ModernMix bundle for $7.99. That takes all the sting out of what people hate about Windows 8.1 by making it much more like Windows 7 (which is also what Windows 10 is all about).
Windows has by far the worse security of any type of computer used in the home today (see Viruses and Junk Software for details).
Don't assume that Anti-Virus software will save you. Everyone has anti-virus software and yet there is still a huge and growing industry that makes billions of dollars a year scamming people with Windows computers. If anti-virus software was invincible that industry would simply not exist.
Read Protecting Windows for advice on how to lock it down as much as possible.
Windows does not automatically backup your files. But you can add an excellent automatic online backup in the form of Carbonite (www.carbonite.com).
Don't skimp on this and think you will be alright with a trusty memory stick and lots of good intentions, it's a recipe for losing a lot of precious data in no time flat. A good quality automatic online backup is the way to stay safe and that description fits Carbonite. They have been around a long time and I personally have done numerous recoveries from them, they always get the files back.
This is where Windows' star shines bright. Because Windows has had such a dominant market share for such a long time almost any type of software or hardware you could possibly think of will run on it. It may be that despite all of its security issues fate will insist you run Windows because it's the only thing that runs the software that you absolutely must have. But before you make that call, read The Key Trade Off. You may find that all the things you thought were impossible in the alternative systems to Windows actually work just fine and you may not need to expose yourself to all the scams to get the things you want and need.
BUT THIS IS ALL NONSENSE!
There's a staggering amount of misinformation and urban myth doing the rounds on the subject of home computers, often nonsense that is most definitely against your best interests. So let's prepare you for when someone "who knows about computers" comes knocking by covering the popular hogwash in advance.
NEIL OBVIOUSLY JUST HATES WINDOWS!
It would be easy to read the text above and assume I have some personal vendetta against Windows. That's not it, it's more nuanced than that. For the record, my favourite user interface for a keyboard and mouse system is Windows 7 (not Windows 8, that's a dog's breakfast and universally hated, although it can be greatly improved with Start8 and ModernMix from Stardock if you are already stuck with it). But of course I'm super careful about what I install on Windows, use it in a very locked down way, have spent the last 38 years learning exactly have to do this stuff safely and it's just one of the types of computers I use.
Where I am coming from is that I have spent the last 10 years trying to keep normal folks safe from computer crime as they use a computer at home. It's like we're trying to cross a chasm with a vicious rapid at the bottom. Windows is the rope bridge taking us across. I am a guide showing people where it's safe to tread and lashing in new bits of rope to hold things together. I get most of them across, but some fall because they don't listen, some fall just because it's a wobbly old bridge with so many gaps. Many try to get across without a guide (most of them fall).
All the time I have been doing this various builders have been constructing other bridges across the chasm, using modern materials like steel and carbon fibre. They don't always carry all the same traffic the old rope bridge does, and people don't use them because they are familiar with the old ways, but no one falls on the new bridges. One day I woke up and thought "What the hell am I doing pouring all this effort into protecting the old ways? Why don't I just help people find a safer bridge?"
So, no, I don't hate Windows. I hate the scumbag criminals who will encrypt the first 5 years of a baby's photos and demand a ransom of the mother to get them back (yes that is a real life example from my day job). It particularly hurts because I know about about how these things work and know that it simply doesn't have to be that way. The technology is capable of eliminating this problem and I want to be part of the solution.
Of course I should point out that the question of what type of computer you should use has become ridiculously tribal. If I object to something in how Windows works there is a large group of people (us geeks call them fanboys, and yes, that word is an insult) who will assume that means I am a fanboy for Macs. Equally, say something negative about the Mac, that tribe will get all very over excited and condemn everything I say, not just on that topic, but on everything I have ever said on any topic (honestly, fanboys really are that stupid. If you have not come across fanboys you really should ready my article on the subject, it will help you understand a lot of the comments you read on the Internet not just on this subject, but on all sorts of things on all sorts of pages). You can see those types of tribes starting to form around the new platforms, people who would only ever use an iPhone, others who think that's heresy and would only use an Android device.
Of course serious geeks don't think that way. We use all the different systems and enjoy what's good about each one in turn. If something is good, we say, if something is bad, we say. Windows has much that is good about it, but giving it to normal folks to play with in the home is like giving a small child an open bottle of bleach and hoping everything will be OK.
Don't be shy, say what you think. The comment system below is there for anyone to ask a question or make a point. Especially don't hold back if you are a normal person just trying to make sense of it all. It's easy to get the opinions of geeks on geeky matters. Much more interesting to hear how this works out for you or what bits need more explanation. No such thing as a silly question, jump in.