Ever since Microsoft first started talking about Windows 7, the next version of Windows that's due for release sometime in late 2009, executives have insisted that companies that migrate from XP to Vista will have far less application compatibility issues later on than those that decide to skip Vista altogether.

But on Thursday at Gartner's Symposium 2008 event in Orlando, Fla., Microsoft CEO Steve Ballmer acknowledged the possibility that some organizations might choose to remain on the sidelines when it comes to deploying Vista.

Responding to a question from Gartner analyst Neil MacDonald about how the current economic environment could affect companies' Vista deployment plans, Ballmer said some might decide to hold off on Vista, and that Microsoft is OK with that.

"If people want to wait, they certainly can," Ballmer said. "I'm not encouraging anyone to wait; I'd go ahead and deploy Windows Vista today."

Larry Piland, president of Datel Systems, a San Diego-based solution provider, says Ballmer's words are an accurate reflection of the stance of his larger customers, for whom the time and expense of migrating to Vista has thus far prevented them from taking the plunge.

"Vista is a great OS, but the problem is, not enough people are aware of it," said Piland. "Many have heard negative rumors about Vista, so they haven't upgraded. And now, they're hearing about a new version [Windows 7] and they're deciding to wait."

Piland estimates that between 60 and 80 percent of his larger customers will decide not to migrate to Vista and wait for Windows 7, but says that number will be far lower for smaller organizations, which have a much easier migration path in terms of implementation costs. But Marc Harrison, president of Silicon East, a solution provider in Manalapan, N.J., was surprised by Ballmer's comment, and says he'll continue to advise his customers to migrate to Vista sooner rather than later.

"I don't see that migrating from Windows XP to Windows 7 will be any different than migrating to Vista now," he said. "The fact is, all the driver and software compatibility issues are behind us. I'm really not sure I can see any benefit in waiting from an end user's point of view."

Joe Toste, vice president of marketing at Equus Computer Systems, a Minneapolis-based system builder, says in the midmarket and enterprise segments, most of his customers have a mix of Windows 2000, XP and Vista desktops because they're continually buying new PCs.

"In fact, we have seen some customers that leveraged Windows 2000 and went directly from a mostly Windows 2000 client to Vista," he said. "As these customers receive more capital expenditure, they retire the older machines. Rarely do you find customers replacing all the machines at one time or in one rollout."

At the Gartner event, MacDonald also asked Ballmer how Microsoft plans to strike the necessary balance between stoking market interest in Windows 7 while also keeping organizations on the Vista upgrade path.

If Microsoft changes too much in Windows 7, it could end up affecting application compatibility, but if it does too little, Windows 7 could end up being perceived merely as Vista R2, MacDonald suggested. "How can we expect anything more than a minor release?" MacDonald asked Ballmer.

"Because it's a lot more work than a minor release It's a release that will do a lot that people want it to do" in terms of performance and adding touch and multi-touch to the user interface, Ballmer said.