This is the question many consumers and professionals will be asking in the coming weeks, as Microsoft cranks the XP hype machine up to full speed. There are arguments in favour of both decisions, and we set them out below.
10 reasons to upgrade...
1) It looks attractive. Hardcore geeks may sniff, but XP is much easier on the eye and its task-oriented user interface does make working more pleasurable. Every little counts.
2) It doesn't crash. Actually, it does -- but much, much less often. If there's a single reason why XP deserves to succeed, it's this. Shame it's taken so long.
3) It works faster. Lots of cleverness under the bonnet goes into wasting less time waiting for stuff to load and run. You soon take it for granted, though.
4) It's easier to use. You'll spend just as much time swearing at applications or cheesy Web sites, but less time trying to get there. One small step for man, one small step for mankind.
5) It does nice things with pictures and sound. Windows Media Player still looks patronising and graceless, but it works better than its predecessor. And if you need an excuse to buy a DV camcorder or a digital camera, the editing tools in XP are your friends.
6) It's easier to support. Chances are, you're first port of call when friends or family sob into their keyboard. Remote Assistance and instant messaging ease those endless phone calls.
7) It knows about CDs and DVDs. You know that unattainable dream, when you just drag and drop music into a writeable CD and everything just works? XP does that. No, we didn't believe it either.
8) It knows about home networks. Truth to tell, so did earlier versions -- but XP has fewer loose ends and kindlier, cleverer wizards.
9) It's better with security. You can keep things safe from hackers, sightseers and even your family.
10) You're going to have to do it sooner or later, so give in gracefully. Resistance is useless.
10 reasons to ignore...
1) You update your computer configuration frequently. Only time will tell how much of a real danger Windows Product Activation will be -- but do you want to nobly lay down your data for Microsoft's sake?
2) It's more expensive than earlier Windows. We can't work this one out. WPA means less piracy, so lower prices, right? Wrong. Microsoft, we won't love you if you do this.
3) It's greedier for your personal data. Register for your Passport! Do it now! NOW! Oh, and have you registered for your Passport?
4) It might not work with your old DOS software. You might not have any old DOS software, of course, but lots of people do. Check first before selling your soul.
5) It might take some time for new drivers to appear for old peripherals. If your life revolves around some ancient networking gear, either budget for new kit or stick with the old software.
6) It's easier to support. Which means, with awful inevitability, that you'll end up doing more unpaid support work because all your computer-illiterate friends will try to do more stuff.
7) The security features are untested. That firewall is Microsoft's first. How many first versions of Microsoft products work properly? Quite. And it's a firewall.
8) It may be too attractive to virus writers. Here, says Microsoft. All your eggs in one easy-to-carry and very pretty basket. Oh, and have you registered for your Passport?
9) It tries to get you to do things the Microsoft way. You might think that AOL IM, ZoneAlarm, WinAmp and so on makes for a safer, more diverse and more effective way of working, XP will not agree.
10) You can do much of what XP does with Windows 9x and free downloads. Although there are many benefits in XP (see above), if you've got a perfectly satisfactory installation of an earlier OS then you really don't need to leap just yet.