Matt Rosoff, an analyst with the independent firm Directions on Microsoft, says that keeping the number of versions high is all part of Microsoft's attempt to segment the market and "maintain the average-price-per-unit of Windows sales in developed countries to counteract the effects of price pressure in developing countries, where most growth is happening."

Rosoff thinks Microsoft's rejiggered lineup is "simpler" for consumers, but remains too complicated for businesses, who will have to "check the feature list carefully" in order to choose between Professional, Enterprise and Ultimate.

Microsoft did consider cutting Ultimate, a pricey, fully-loaded version that in Windows Vista was aimed at gamers and enthusiasts.

"We're keeping it because a lot of top [PC makers] wanted it in order to let them differentiate their own hardware," Ybarra said.

Windows 7 Ultimate won't have any unique multimedia features, but will share the same advanced networking and security features as Windows 7 Enterprise, which is available to large corporations through volume licensing, Ybarra said.