Everyone keeps talking about five years. Five years since the release of Windows XP, five years to develop and push Vista out the door.

But Microsoft wants you to double that number, and recall the monumental launch of Windows 95 that coincided with an Office suite upgrade, culminating in the biggest festival Redmond has ever seen. I remember how the cumulous clouds in the blue Redmond sky eerily matched the software's packaging (like Bill Gates ordered them up for the event), and the nightly newscast featured video of people standing in lines at computer stores into the wee hours to buy the software.The launch of Vista, Office 2007 and Exchange Server 2007, according to Microsoft, is a comparable event.

In an interview last week, Microsoft corporate VP Mike Sievert told me the releases mark a "huge moment" for the tech industry, since it's been more than 10 years since the company has had an introduction that spans the operating system to productivity software to collaboration. The releases, Sievert said, are "so well-timed, and so well-tuned to our major customer trends."

Or are they? Is this troika as monumental as Microsoft would like you to believe? An all-in-one must have?

Vista unquestionably has significant visual appeal over Windows XP, with programmable mini apps on the desktop and a powerful graphics engine. It's got improved search capabilities, much-needed security and mobility features, automatic data synchronization to back-up systems, and a new imaging format for easier deployment across a business.

Office Sharepoint Server is Microsoft's big collaboration play, with enterprise search capabilities via XML plug-ins to back-end systems, and platforms for creating and managing wikis and blogs. And key to Exchange 2007 is unified messaging: voicemail messages are routed to the desktop.

Indeed, Microsoft has put together an impressive desktop computing platform that it must have updated many times along the way (I'm guessing they weren't thinking about blogs and wikis in 2001). But the big difference since it's last grandiose release in 1995, of course, is the Web and all it has to offer as a productivity platform. What applications really need to be on the desktop? Does the Web (with easy access from any device via a browser) make more sense for collaboration? Will Microsoft's offerings seem too proprietary in an increasingly open-source world?

Well, I don't believe Microsoft is necessarily in danger of losing desktop customers, particularly big business. One CIO of a consumer goods company I talked to said that of course they'll migrate to the new releases-the Windows platform has proved itself again and again in terms of total cost of ownership. When you've got thousands of desktops and laptops worldwide, you need a standard way of doing things. No question, most customers will eventually migrate.

But what will the newer, younger, growing companies do? Or those that have the flexibility (or sheer guts) to try something different, that's potentially easier or cheaper? And if they're proved right, how fast will the word spread?

The value of Microsoft's technologies and products isn't questionable; otherwise it wouldn't still be king of the desktop. Indeed, all those companies trying out a Web-based or open-source alternative could come running back to Microsoft in search of something more standard, robust and consistent.

Or not.

Either way, I'm pulling up a seat and grabbing some popcorn. Desktop computing and collaboration, and the direction they take, will be an interesting show for years to come.