Well, now you don't have any choice: Microsoft will no longer sell you a copy of Windows XP. If you want to buy Windows for your desktop PC, it has to be Vista (although you may find there's still the odd small PC assembler around who will still recommend you stick with XP).

For my part, I don't mind at all. First, I do most of my work with a Macintosh, but that's another story; second, the PC I do use is so pumped up (I'm skiting again) that it runs Vista with complete ease. Vista may be huge and bloated, but I don't care: My PC has a huge and bloated 750GB hard drive to match. Vista may be slow, but not if you're running a quad core CPU; even a dual core CPU is good enough, and that's pretty much standard issue these days.

Vista gobbles up memory? Probably but memory is cheap too, which is why I'm using 4GB (and 64-bit Vista - most people will be happy with the 32-bit version and 2GB).

But a year ago, when I had my old PC, I was very unhappy with Vista. Everything it did with satisfactory speed on Windows XP had suddenly become sluggish - particularly the speech recognition functions I used to help me write, which became completely unusable with Vista.

Unfortunately it's also true that my PC was about five years old, which Ben Green, Windows client and mobile marketing manager for Microsoft New Zealand, tells me is about how long we try to hang on to PCs for in this country. This is sad; back in the 1980s it was reasonable to expect PCs to fit into the same depreciation schedule as other items of office equipment such as desks and chairs, but we should know better now. Forget having a PC last as long as a filing cabinet - filing cabinets, for example, haven't had to cope with average document sizes multiplying in size over the past 10 years, as emails have done thanks to broadband and attached JPEGs.

PCs really do have to work in a constantly changing social context; by all means blame Microsoft for changing the standard formats of word processor and spreadsheet documents so that your old software won't read new documents, but they're not the only ones. The standards used for constructing web documents is evolving constantly too, and if your web browser can't display data in tabbed pages then it's probably too old to cope with a growing percentage of CSS-based pages on the web (CSS and tabbed viewing are unrelated, but as a rule of thumb browsers that don't do tabs are too old to work properly now).

"We know there's a gap between what Vista is and what people think it is," Mr Green said. "The perception gap is not positive among people who haven't actually used Vista, or if they have, they used it early on. Now that Vista Service Pack One (SP1) is out, the product is quite different from what it was at release time."

It's also easy to forget some of the issues that Vista was designed to cope with - particularly security. "We re-wrote the security model for Vista, and what we've delivered is the most secure operating system we've ever made," Mr Green said. And indeed, according to independent security experts, Vista is the most secure commercially available desktop operating system - you can't infect it with malware unless you deliberately give it permission to become infected, although it's probably still a good idea to install some anti-virus software such as AVG's free anti-virus product, or a more comprehensive anti-malware suite from AVG, Symantec or McAfee.

Microsoft has a whole checklist of up-beat Vista features: it is the fastest selling Windows ever, with over 140 million copies sold up to April this year; at its release it may not have been very compatible with third party devices and components, with support for a mere 20,000 devices, but they've added another 57,000 since then; nearly all the most popular consumer applications now work with Vista; and since SP1 came out, performance is pretty much on a par with Windows XP.

So now Vista works as well as it should have in the first place and is much more secure than its predecessors. It is also the model for the future - perhaps as a result of the early complaints Microsoft has said more about the next version of Windows than it might be expected to so soon after a major release like Vista. Windows 7 (as it will be called, although Microsoft's numbering system here is difficult to understand) will appear early in 2010, will support new technologies such as multi-touch track pads (adds manoeuvrability) and the surface display devices Microsoft showed at the Consumer Electronics Show in Las Vegas earlier this year.

It will also be built on the same core code as Vista and other versions of Windows going back to Windows NT, which suggests that most changes are likely to be tweaks to superficial elements such as usability. Not that Windows wouldn't benefit greatly from being made easier to use - but its fundamental performance is unlikely to change much.

So the wait for some kind of Windows nirvana will be a one - Windows will probably always expand to use the full capabilities of whatever hardware it's run on. If you have an old PC, Windows XP is the best version of Windows for it. If you have a new PC, be glad that it comes with Vista. And if you're planning on buying a PC sometime in 2010 - it will probably run like a slug, at least until Windows 7 SP1 comes out.