It was quite obvious that Windows 8 would support USB 3.0 and today Steven Sinofsky at Building Windows 8 blog has confirmed that the next generation operating system would support USB 3.0. The blog reads that by 2015 all the new PC would provide USB 3.0 support. Here is what Steven posted on the blog-
With throughput up to 10 times faster than USB 2.0 and improved power management that results in longer battery life, USB 3.0 introduces compelling reasons to improve the world’s most popular PC interface. By 2015, all new PCs are expected to offer USB 3.0 ports, and over 2 billion new "SuperSpeed" USB devices will be sold in that year alone.
Microsoft also created a "Microsoft USB Test Tool" (MUTT) to simulate device behaviors and test USB 3.0 compatibility. The blog reads- “The MUTT was born – think of it as 1,000 devices on a USB thumb drive”
As USB 3.0 would be 10 times faster than USB 2.0 you’d be able to copy a high definition movie from a USB storage drive in about 80 seconds instead of the 15 minutes it takes with USB 2.0 as the transfer speed would be around 5 Gbps.