The Microsoft co-founder-turned-philanthropist, is unsurprisingly over the moon with the the re-imagined OS, which the company will unleash upon the world on Oct. 26.
In an interview with Steve Clayton of Microsoft's Next Blog, the chairman of the Softies said the touch-friendly software is a huge step and represents the future of personal computing.
"This is an absolutely critical product," Gates said. "It takes Windows into the world of touch...really giving people what you think of as the best of a tablet-type experience and the PC experience.
"It's a big step, it's key to where personal computing is going and we're going to get software developers behind this like we have with every new version of Windows."
Surface must be seen to be believed
Gates, who rarely comments on product matters these days, also waxed lyrical about the merits of the new Microsoft Surface RT tablet, which also goes on sale this week.
He said he's been using the device night and day and promised it would also embody the perfect blend of the tablet and traditional PC experience that users are demanding.
"Surface is an unbelievably great product," he said.
"It embodies this idea of 'can you get an even better tablet that also has what you expect in a PC?' With a stand, a keyboard, the ability to point at things, which also gives you access to some of the classic software like Office.
"I've been using my Surface RT day and night, showing it to everyone I meet. But you can't appreciate it without seeing it. People, get to a store and play around with this thing."
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A technology journalist, writer and videographer of many magazines and websites including T3, Gadget Magazine and TechRadar.com. He specializes in applications for smartphones, tablets and handheld devices, with bylines also at The Guardian, WIRED, Trusted Reviews and Wareable. Chris is also the podcast host for The Liverpool Way. As well as tech and football, Chris is a pop-punk fan and enjoys the art of wrasslin'.