Combining 5 Gbps with the convenience of USB sounds like a sure win. The idea is is simple. Just start with widely used, fast, and bulletproof USB 2.0 and put in the PHY (physical-layer) interface from another common and reliable standard, PCIe (peripheral-component-interconnect express) Generation 2. Put two extra differential pairs into the USB connector to carry the new high-speed serial signals. Getting this all to work well is not simple and there are still many issues that are hiding behind the premise. EDN magazine article USB 3.0: A simple idea full of challenges tells you those issues.
Besides getting the hardware working there is still long way until there are well working drivers for all operating system. It looks like Linux will be the first OS to support USB 3.0. Sarah Sharp has made xHCI (USB 3.0) host controller driver and initial support for USB 3.0 devices for Linux operating system. This makes Linux the first operating system to support the USB 3 standard.