Microsoft's next operating system - initially roadmapped to appear two years ago - won't be with us until after Christmas. As long as there's been a Microsoft Windows, it's been synonymous with slippage, and this isn't the first time that Vista has been pushed back. But it's by far the most dramatic Vista delay.

It's not good news for Microsoft, which would presumably like to sell lots of copies of the new OS sooner rather than later. On the other hand, most of the PCs that get sold this Christmas will still have a Microsoft OS on them - it'll just be one called Windows XP. And it's a gigantic issue for the computer industry - possibly a catastrophic one for some vendors. It's not just that a new OS is a huge incentive to buy a PC; it's that the lack of a new OS is a strong disincentive to buy, since the simplest way to get a new version of Windows is to buy a system that has it preinstalled.

Already, hardware manufacturers were fretting over the fact that a lot of people were putting off PC purchases until late this year. Now a lot of clever consumers will struggle on with the computer they've got until 2007 - and that spells bad news for the all-important back-to-school and holiday seasons. The stores that sell PCs will suffer; even manufacturers of printers and networking equipment and practically anything else that talks to Windows may see their sales drop.

So this is bad news for the Behemoth of Redmond and the companies who sell products based on its platform. The question remains: should you, as a Windows user, be dejected?

And the answer is pretty simple: not really (unless you're the type of geek who camps out at PC World to await a new version of Windows - and we really hope you aren't). First of all, we're talking about a few weeks here; if you're looking forward to Vista, you'll get it soon enough. Any PC that can survive in a useable state until December can surely squeak into 2007; if it can't, you can always buy a new system and upgrade later.

Then there's Microsoft's explanation for the delay: it needs more time to get Vista security right. That's a pretty darn good excuse; any sane Microsoft customer should be happy to wait a bit longer for a more secure, stable OS. Some - especially in big companies - will wait a long, long time: for many corporations, Vista won't be a factor until 2008, and maybe later.

Ultimately, though, the real question about Vista is whether it's going to be a dramatic enough advance on XP that it's worth devoting any brain cells at all to stressing out over its whereabouts. The jury will be out on that one until there's a more-or-less final version to try. But it's hard envisioning it being a Windows 95-like blockbuster. The good news: it seems unlikely that it'll be a Windows Me-style fiasco.

What looks most promising about Vista? It should indeed be more secure, although as we've said, we think features such as User Account Protection will create problems as well as solve them. It'll have decent built-in search, some worthwhile photo- and music-related features, and widgets (er, Gadgets). It'll look prettier than Windows XP, but perhaps not as nice as Mac OS X. It'll have some usability tweaks, although the beta we've seen provides a less consistent user interface than XP. It'll have a new version of IE. And it'll be the first mainstream version of Windows that can truly take advantage of 64bit PCs.

That last point may be, long-term, the most important thing about Vista - but it's a virtue that'll make itself apparent over the next few years, not in January 2007.

There are, in other words, a load of reasons to consider Windows Vista... and once it hits new PCs and the first glitches and driver issues are worked out, it should be a better Windows than XP. But it's still hard to find any one feature that should leave a sensible PC user salivating - or even a few of them that add up to a big deal.

In part, we think, that's because of the web's gigantic impact on how software is created, distributed and subsidised. A lot of the innovation in Vista got here long before the OS will, and you don't even need to pay for it.

Want a better firewall than XP's built-in one? ZoneAlarm and other products are available right now - for free. Covet widgety little applets? The Yahoo Widget Engine (nee Konfabulator) is cool, mature - and free. Trying to organise your photos? Google's Picasa isn't perfect, but it's a lot of fun - and free. Need desktop search? There are so many options that I'm not going to bother linking to any of them - and they're free.

Building a new version of Windows is still a massive engineering challenge that takes years, and Microsoft's entire business model is based around asking people to pay for it, whether you pay for the upgrade on a CD or simply buy a Vista machine. That seems archaic in an age when the Googles of the world can push out new products on the web, update them frequently, and (in theory, at least) give 'em away.

There was a time when most of the innovation in the world of software happened on the desktop. Today, though, the real action is on the web - and small companies such as Riya are doing things which are more viscerally exciting than anything we've seen in Vista so far. And much of the cool stuff you can do on the web can be done in any major browser on any OS.

What can't the web do? Right now, at least, it can't really talk directly to cool hardware. An OS can and, as we say, Windows Vista's 64bittishness is more tantalising than its functionality. Perhaps the future of operating systems lies not in tools and features so much as in leveraging the CPU and powerful graphics cards and networking and other hardware to let web services (and, oh, desktop applications) do their thing. If so, that would be in some ways a return to the DOS days, when an operating system was more like a layer of glue than an environment you spent much time in.

Anyhow, a Vista which had been available in 2006 would have been less than a milestone in the history of computing; one which slips into next year will need to struggle even more to assert its relevance in the age of the web. We think there's a chance that when we all look back in a decade or two, this delay will be remembered as a milestone... in the gradual decline of Windows in particular and desktop operating systems in general. We'll see.

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