Win 95 was far from brilliant when it came out. There were 4 service packs for 95, it used to be unstable as hell due to a number of design flaws that pesisted all the way through Win98 and Win ME (which are explained in greater detail
here. 98 was more of the same, there was a couple of service packs for that, and let's not forget that it crashed with a BSOD before a live audience when Bill Gates was announcing it to the world. ME, well, its status as a poor operating system is legendary. It did nothing better than 98 but just hid all the DOS mode functions when there was still a lot of legacy applications that used it.
It was this instability of the win9x kernel that really started a push for 'linux on the desktop' because it didn't suffer from the flaws that could cause Win9x to crash. At the time it was infinitely more stable. After XP became the standard though, this isn't really the case and generally linux is no more stable than Xp/vista/Win7. A lack of commercial software to run on linux, and the wildly varying quality of open source applications really only leaves the cost factor in linux's favour as a desktop OS. It also doesn't help that there is a total lack of consistency between linux distributions, so even someone who is cluey with one distribution of linux might be scratching their head if they try to use a different one. Its useful as a server OS but even then, there's a saying that 'linux is only free if your time is worthless'. Sometimes it might be worth paying for a commercial product that 'just works' and has vendor support, rather than fiddling with open source software to try and achieve the same thing. Having said that, I have a couple of linux servers at work that do what they are supposed to quite well, but really, I don't think linux is ever going to be more than a novelty on the desktop.
Many years ago I dual booted Mandrake linux and Win2k, I would surf the web/type up schoolwork in linux and reboot into windows when I wanted to play a game or use an app that wasn't available on linux. after a while though I sort of realised that windows was capable of doing everything I needed and I was really just wasting time swapping OS's constantly so I stuck with windows.
Even XP has had several service packs, and Virgil is right when he says it was a dog when it came out, I remember it quite vividly. When I was using Win2k at home it was always faster then XP was. As the average user's hardware became faster, and manufacturers got more comfortable with writing XP compatible drivers, XP improved exponentially. Let's not forget things like blaster and sasser that took out pc's all over the world due to flaws in XP's code.
I was using Vista ultimate until recently and really, the only thing that was bad about it was UAC which is pretty easy to disable. I had pretty fast hardware so it wasn't any slower than XP on my machine really. Karnage if your friends computer is crashing all the time with vista I would suggest that either he has a hardware problem or he did something silly like download a porno that ends in .exe - i.e. its not vista's fault.
I currently use win 7 pro merely because I got a cheap licence. UAC is improved and I haven't bothered to disable it, but apart from that there's not a great deal that's improved over vista. I'm kind of undecided on the application stacking on the taskbar, it can be annoying sometimes. Really I could go either way on vista/win7.
Also remember the
mojave experiment where people liked vista if you didn't tell them what it was. This is what I mean by bandwagon, as psychokyller said 'everyone is on the bandwagon' - well that's pretty much the definition of a bandwagon, everyone jumps on because they don't bother to think for themselves and make their own opinion. I've heard people say that vista sucks but nobody can say exactly why. The only thing I can really fault with it is UAC which you can turn off anyway.
As for mac, well I've used Mac OSX for a bit on other people's machines and it does things a bit differently but I wouldn't necessarily say better. I could use it if I had to but I don't see why I would pick it over windows. if every application I wanted to use was available on mac OSX I'd probably use it but I can't really justify the price premium. I build my own PC's and I don't care if my computer's case looks a bit flashier, I'm busy looking at the screen not the case. If people want to pay extra for it then that's their prerogative. I don't necessarily think mac OSX is any easier to use that windows either, both do thing their own way and both have their learning curve. If anything I find its more annoying trying to find configuration settings on the mac compared to windows. I've also seen Mac OSX suffer from 'performance rot', my one-time flatmate had a powerPC based macbook that really bogged down from all the shit he used to install for uni. He ended up taking it to apple for service who reformatted it. Also, contrary to popular belief, there are viruses for macs and Apple is actually pretty abysmal at patching security holes compared to microsoft.
at the end of the day, just use whatever the fuck you like. They each do things differently so use whichever appeals to you most.
my earliest os were DOS and windows 3.11
Same

until recently I had an old 486 that I used to boot up and tool around with. It gave a real sense of accomplishment to free up enough conventional or EMS memory to play some of the more finicky games... you felt like you earned the right to play
