Sorry, Linux desktop fans: When it comes to desktop operating systems, it's currently a two-way race between Windows and the Mac OS. While Microsoft's market share dwarfs Apple's, the GUI diehards have keep each other busy for nearly two decades - and end users have regularly reaped the benefits of that competition, thanks to upgrades designed to top the competition's features and performance.

This week, the cross-platform debate's been hot and heavy. Is Microsoft racing to catch up to Panther, the Mac OS X upgrade due to roll out at June's Worldwide Developers Conference? Should Apple be running scared after Microsoft's demos of its Longhorn OS at last week's Windows Hardware Engineering conference?

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