> Istalling a new more powerful graphics card.
> It's been made super easy to do in windows, but a ball ache in linux.
Sorry but you can't generalise from one example. I have seen it go both ways: network cards that Windows would absolutely refuse to recognise and which worked fine under Linux. Video card swaps/additions have never presented a problem to me on Linux, but I do not doubt there are examples to the contrary out there.
It is just the nature of the beast, the only way to avoid this problem is going the Apple "closed garden" way of selling you both the software and the hardware to run it on. That in itself has its own pros and cons.
> this is why someone wouldn't choose the various (and basically confusing number of) linux distros
Can you offer any evidence to back that up, please?
As for the "basically confusing", is it still the case that each Windows version (there are four of them out there which are currently supported, MS' website tells me) comes in different "flavours" such as "Home", "Professional", etc.? I'm sure they would be straightforward to tell apart by regular Windows users, yet they were utterly confusing to the uninitiated, like me.
In any event, the different distros are simply different operating systems, built around a common base and very similar to each other. Which one you use is more a matter of preference than any real differences--for a home user, you can start with *any* of them and spin it for a while, if you don't like it you can change at any point. Your data will be kept, as will most of your configuration. For professional uses (e.g., as a platform for some service or product that you're developing), you need to make your research, but the breadth of choice comes as a great advantage.
NB: I do not really care what you or anyone else use as their OS of choice for work or play. There is a market out there for all major players, be they free or proprietary, and I hope all of them (including Windows) will stay relevant for a long time so their public won't be disappointed. I just want to respond to what I consider baseless generalisations and unjustified preconceptions.